Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Mar. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative asset counterparty credit valuation adjustment		$ 2	$ 1
Fair value, amount transferred from level 1 to level 2	$ 10	47
Fair value, amount transferred from level 2 to level 1	15	15
Fair value, amount transferred from level 3 to level 2		4
Finance receivables from related party	108	108	94
Receivables from direct finance leases	$ 20	$ 20	308
Maximum [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative liability non-performance credit valuation adjustment			$ 1