Installment Receivables (Activity in the Deferred Interest and Allowance for Credit Losses for the Installment Receivables) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Deferred interest and allowance for credit losses, beginning of period	$ 0	$ 329
Bad debt expense	93
Write-offs, net of recoveries	(105)
Change in deferred interest on short-term and long-term installment receivables	(43)
Derecognition of deferred interest and allowance for credit losses	$ (274)	0
Successor [Member] | Financing Receivable [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Deferred interest and allowance for credit losses, beginning of period		329	$ 124
Bad debt expense		398
Write-offs, net of recoveries		(255)
Change in deferred interest on short-term and long-term installment receivables		$ 62