Selected Quarterly Financial Data (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Selected Quarterly Financial Data (Unaudited) [Abstract]
Total financing revenues	$ 1,795	$ 1,797
Depreciation on operating leases	951	855
Interest expense	536	58
Net financing revenues	308	884
Provision for credit losses	11	16
Income before income taxes	144	756
Provision for income taxes	53	279
Net income	$ 91	$ 477