Derivatives (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Interest rate lock commitments | Gain on mortgage loans, net
Derivatives
Gains (losses) on derivative instruments	$ 67	$ 374	$ 269	$ 760
Forward delivery commitments | Gain on mortgage loans, net
Derivatives
Gains (losses) on derivative instruments	185	(124)	239	(153)
Option contracts | Gain on mortgage loans, net
Derivatives
Gains (losses) on derivative instruments	20	(6)	18	(10)
MSR-related agreements | Net derivative (loss) gain related to mortgage servicing rights
Derivatives
Gains (losses) on derivative instruments	(1)	2	(17)	(3)
Interest rate contracts | Fleet interest expense
Derivatives
Gains (losses) on derivative instruments		(1)		(1)
Foreign exchange contracts | Fleet interest expense
Derivatives
Gains (losses) on derivative instruments		$ 1		$ 1