Long-Term Debt (Committed Funding Facilities) (Details) - Committed Funding Facilities [Member] - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Outstanding	$ 21,077	$ 18,280
Unused capacity	1,295	3,675
Total capacity	22,372	21,955
Bank Funding Member | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	3,015	3,250
Unused capacity	235	250
Total capacity	3,250	3,500
Nonbank Funding [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Outstanding	18,062	15,030
Unused capacity	1,060	3,425
Total capacity	19,122	$ 18,455
Revolving secured funding facilities [Member]
Debt Instrument [Line Items]
Total capacity	21,700
Revolving secured funding facilities 1 year or greater [Member]
Debt Instrument [Line Items]
Total capacity	$ 17,900