Long-Term Debt (Committed Funding Facilities) (Details) (Committed Funding Facilities [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Outstanding	$ 18,509	$ 17,909
Unused capacity	4,617	6,747
Total capacity	23,126	24,656
Bank Funding Member | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	2,500	2,750
Unused capacity	1,000	250
Total capacity	3,500	3,000
Nonbank Funding [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	16,009	15,159
Unused capacity	3,617	6,497
Total capacity	19,626	21,656
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Total capacity	20,900
Revolving secured funding facilities 1 year or greater [Member]
Debt Instrument [Line Items]
Total capacity	$ 11,000