Fair Values - Not Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Card Member loans
Fair Values (Textuals)
Financing receivables, gross	$ 151,832	$ 139,674
Card Member receivables
Fair Values (Textuals)
Financing receivables, gross	62,031	59,411
Variable Interest Entity, Primary Beneficiary | Card Member loans
Fair Values (Textuals)
Financing receivables, gross	27,719	28,278
Variable Interest Entity, Primary Beneficiary | Card Member receivables
Fair Values (Textuals)
Financing receivables, gross	5,659	3,927
Carrying Value
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	48,000	41,000
Other financial assets	66,000	63,000
Financial assets carried at other than fair value
Card Member and Other loans, less reserves		143,000
Financial liabilities for which carrying values equal or approximate fair value	166,000	155,000
Financial liabilities carried at other than fair value
Long-term debt	56,000	50,000
Carrying Value | Certificates of deposit
Financial Liabilities:
Financial liabilities	16,000	12,000
Financial liabilities carried at other than fair value
Financial liabilities	16,000	12,000
Carrying Value | Card Member loans
Financial assets carried at other than fair value
Card Member and Other loans, less reserves	157,000
Carrying Value | Card Member loans HFS
Financial assets carried at other than fair value
Card Member loans HFS	2,000	1,000
Corresponding Fair Value Amount
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	48,000	41,000
Other financial assets	66,000	63,000
Financial assets carried at other than fair value
Financial liabilities for which carrying values equal or approximate fair value	166,000	155,000
Corresponding Fair Value Amount | Variable Interest Entity, Primary Beneficiary | Card Member receivables
Fair Values (Textuals)
Financing receivables, gross	5,600	3,900
Corresponding Fair Value Amount | Fair Value, Inputs, Level 1
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	46,000	39,000
Other financial assets	0	0
Financial assets carried at other than fair value
Financial liabilities for which carrying values equal or approximate fair value	0	0
Corresponding Fair Value Amount | Fair Value, Inputs, Level 2
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	2,000	2,000
Other financial assets	66,000	63,000
Financial assets carried at other than fair value
Financial liabilities for which carrying values equal or approximate fair value	166,000	155,000
Corresponding Fair Value Amount | Fair Value, Inputs, Level 3
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	0	0
Other financial assets	0	0
Financial assets carried at other than fair value
Financial liabilities for which carrying values equal or approximate fair value	0	0
Portion at Other than Fair Value Measurement
Financial assets carried at other than fair value
Card Member and Other loans, less reserves		149,000
Financial liabilities carried at other than fair value
Long-term debt	57,000	50,000
Portion at Other than Fair Value Measurement | Certificates of deposit
Financial Liabilities:
Financial liabilities	16,000	12,000
Financial liabilities carried at other than fair value
Financial liabilities	16,000	12,000
Portion at Other than Fair Value Measurement | Card Member loans
Financial assets carried at other than fair value
Card Member and Other loans, less reserves	162,000
Portion at Other than Fair Value Measurement | Card Member loans HFS
Financial assets carried at other than fair value
Card Member loans HFS	2,000	1,000
Portion at Other than Fair Value Measurement | Variable Interest Entity, Primary Beneficiary
Financial liabilities carried at other than fair value
Long-term debt	13,300	14,000
Portion at Other than Fair Value Measurement | Variable Interest Entity, Primary Beneficiary | Card Member loans
Fair Values (Textuals)
Financing receivables, gross	27,600	28,300
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 1
Financial assets carried at other than fair value
Card Member and Other loans, less reserves		0
Financial liabilities carried at other than fair value
Long-term debt	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 1 | Certificates of deposit
Financial Liabilities:
Financial liabilities	0	0
Financial liabilities carried at other than fair value
Financial liabilities	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 1 | Card Member loans
Financial assets carried at other than fair value
Card Member and Other loans, less reserves	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 1 | Card Member loans HFS
Financial assets carried at other than fair value
Card Member loans HFS	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 2
Financial assets carried at other than fair value
Card Member and Other loans, less reserves		0
Financial liabilities carried at other than fair value
Long-term debt	57,000	50,000
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 2 | Certificates of deposit
Financial Liabilities:
Financial liabilities	16,000	12,000
Financial liabilities carried at other than fair value
Financial liabilities	16,000	12,000
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 2 | Card Member loans
Financial assets carried at other than fair value
Card Member and Other loans, less reserves	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 2 | Card Member loans HFS
Financial assets carried at other than fair value
Card Member loans HFS	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 3
Financial assets carried at other than fair value
Card Member and Other loans, less reserves		149,000
Financial liabilities carried at other than fair value
Long-term debt	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 3 | Certificates of deposit
Financial Liabilities:
Financial liabilities	0	0
Financial liabilities carried at other than fair value
Financial liabilities	0	0
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 3 | Card Member loans
Financial assets carried at other than fair value
Card Member and Other loans, less reserves	162,000
Portion at Other than Fair Value Measurement | Fair Value, Inputs, Level 3 | Card Member loans HFS
Financial assets carried at other than fair value
Card Member loans HFS	$ 2,000	$ 1,000