Consolidations and Transfers of Financial Assets WAC, WALA, WAM (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Transfers of Financial Assets [Line Items]
Unpaid principal balance portfolio securitizations	$ 55,400	$ 44,200	$ 166,300	$ 113,100
Unconsolidated VIEs [Member]
Transfers of Financial Assets [Line Items]
Principal and interest received on retained interests	273	$ 386	919	$ 1,100
Unconsolidated VIEs [Member] | Single Class MBS, REMIC & Megas [Member]
Transfers of Financial Assets [Line Items]
Unpaid principal balance of retained interests	5,400		5,400		$ 6,300
Fair value of retained interests	$ 6,700		$ 6,700		$ 7,600