Allowance for Credit Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Allowance for Credit Losses on Finance Receivables and Investments in Operating Leases
Allowance for credit losses at	$ 447	$ 501	$ 454	$ 527
Provision for credit losses	79	28	117	39
Charge-offs, net of recoveries	(81)	(62)	(126)	(99)
Allowance for credit losses at	445	467	445	467
Recoveries from credit loss charge-offs	$ 20	$ 21	$ 42	$ 45