Loan Receivables and Allowance for Credit Losses - Schedule of Loans Modified in Past 12 Months And Still In Program (Details) $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($) payment	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Financing Receivable, Modified [Line Items]
Number of consecutive monthly program payments, return to current status \| payment	3
Financial Asset, Not Past Due
Financing Receivable, Modified [Line Items]
Total loans modified	$ 993	$ 1,056	$ 916
% of Total Class of Loan Receivables	1.00%	1.00%	0.90%
30-89 days delinquent
Financing Receivable, Modified [Line Items]
Total loans modified	$ 188	$ 207	$ 213
% of Total Class of Loan Receivables	0.20%	0.20%	0.20%
90 or more days delinquent
Financing Receivable, Modified [Line Items]
Total loans modified	$ 149	$ 182	$ 183
% of Total Class of Loan Receivables	0.10%	0.20%	0.20%
Total past due
Financing Receivable, Modified [Line Items]
Total loans modified	$ 337	$ 389	$ 396
% of Total Class of Loan Receivables	0.30%	0.40%	0.40%
Credit cards \| Financial Asset, Not Past Due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	$ 935	$ 987	$ 861
Credit cards \| Financial Asset, Not Past Due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	54	65	53
Credit cards \| 30-89 days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	157	169	180
Credit cards \| 30-89 days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	30	37	32
Credit cards \| 90 or more days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	112	136	141
Credit cards \| 90 or more days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	36	45	41
Credit cards \| Total past due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	269	305	321
Credit cards \| Total past due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	66	82	73
Consumer installment loans \| Financial Asset, Not Past Due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| Financial Asset, Not Past Due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| 30-89 days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| 30-89 days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| 90 or more days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| 90 or more days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| Total past due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Consumer installment loans \| Total past due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Commercial credit products \| Financial Asset, Not Past Due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	4	4	2
Commercial credit products \| Financial Asset, Not Past Due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Commercial credit products \| 30-89 days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	1	1	1
Commercial credit products \| 30-89 days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Commercial credit products \| 90 or more days delinquent \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	1	1	1
Commercial credit products \| 90 or more days delinquent \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	0	0	0
Commercial credit products \| Total past due \| Long-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	2	2	2
Commercial credit products \| Total past due \| Short-term Modification
Financing Receivable, Modified [Line Items]
Total loans modified	$ 0	$ 0	$ 0

Synchrony Financial 10-K