Fair Value (Details 1) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Financial assets carried at other than fair value [Abstract]
Card Member loans, less reserves	$ 413	$ 398
Loans to affiliates and other	11,429	15,303
Financial liabilities carried at other than fair value [Abstract]
Long-term Debt	22,177	24,282
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Financial Assets:
Financial assets for which carrying values equal or approximate fair value	20,000	16,800
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	7,400	6,000
Level 2 [Member]
Financial Assets:
Financial assets for which carrying values equal or approximate fair value	19,900	16,800
Financial assets carried at other than fair value [Abstract]
Card Member loans, less reserves	0	0
Loans to affiliates and other	8,300	12,300
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	7,400	6,000
Financial liabilities carried at other than fair value [Abstract]
Long-term Debt	22,300	24,500
Fair Value, Inputs, Level 3 [Member]
Financial Assets:
Financial assets for which carrying values equal or approximate fair value	0	0
Financial assets carried at other than fair value [Abstract]
Card Member loans, less reserves	400	400
Loans to affiliates and other	3,000	2,900
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	0	0
Financial liabilities carried at other than fair value [Abstract]
Long-term Debt	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial Assets:
Financial assets for which carrying values equal or approximate fair value	20,000	16,800
Financial assets carried at other than fair value [Abstract]
Card Member loans, less reserves	400	400
Loans to affiliates and other	11,300	15,200
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	7,400	6,000
Financial liabilities carried at other than fair value [Abstract]
Long-term Debt	22,300	$ 24,500
FairValueInputsLevel1Member
Financial Assets:
Financial assets for which carrying values equal or approximate fair value	$ 100