Fair Values (Details 2) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	$ 18,430,000,000	$ 19,486,000,000	$ 23,129,000,000	$ 22,250,000,000
Financial liabilities carried at other than fair value
Certificates of deposit	6,293,000,000
Long-term debt	54,836,000,000	55,330,000,000
Fair Values (Textuals) [Abstract]
Accounts receivable, less reserves	44,893,000,000	43,777,000,000
Card Member loans, net	65,168,000,000	65,977,000,000
Variable Interest Enterprise [Member]
Financial liabilities carried at other than fair value
Long-term debt	15,499,000,000	18,690,000,000
Carrying Value [Member]
Financial assets for which carrying values equal or approximate fair value
Other financial assets	49,000,000,000	48,000,000,000
Financial assets carried at other than fair value
Loans, net	66,000,000,000	67,000,000,000
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	60,000,000,000	60,000,000,000
Financial liabilities carried at other than fair value
Certificates of deposit		7,000,000,000
Long-term debt	55,000,000,000	55,000,000,000
Estimate of Fair Value, Fair Value Disclosure [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	18,000,000,000	19,000,000,000
Other financial assets	49,000,000,000	48,000,000,000
Financial assets carried at other than fair value
Loans, net	66,000,000,000	67,000,000,000
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	60,000,000,000	60,000,000,000
Financial liabilities carried at other than fair value
Certificates of deposit	6,000,000,000	8,000,000,000
Long-term debt	57,000,000,000	58,000,000,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Variable Interest Enterprise [Member]
Financial liabilities carried at other than fair value
Long-term debt	15,600,000,000	18,800,000,000
Fair Values (Textuals) [Abstract]
Accounts receivable, less reserves	6,500,000,000	7,300,000,000
Card Member loans, net	28,700,000,000	31,000,000,000
Level 1 [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	17,000,000,000	17,000,000,000
Other financial assets	0	0
Financial assets carried at other than fair value
Loans, net	0	0
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	0	0
Financial liabilities carried at other than fair value
Certificates of deposit	0	0
Long-term debt	0	0
Level 2 [Member]
Financial assets for which carrying values equal or approximate fair value
Cash and cash equivalents	1,000,000,000	2,000,000,000
Other financial assets	49,000,000,000	48,000,000,000
Financial assets carried at other than fair value
Loans, net	0	0
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	60,000,000,000	60,000,000,000
Financial liabilities carried at other than fair value
Certificates of deposit	6,000,000,000	8,000,000,000
Long-term debt	57,000,000,000	58,000,000,000
Level 3 [Member]
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
Loans, net	66,000,000,000	67,000,000,000
Financial Liabilities:
Financial liabilities for which carrying values equal or approximate fair value	0	0
Financial liabilities carried at other than fair value
Certificates of deposit	0	0
Long-term debt	$ 0	$ 0