Installment Receivables Activity in the deferred interest and allowance for credit losses for the installment receivables (Details) (Successor [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Mar. 31, 2014	Sep. 30, 2014
Successor [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Deferred interest and allowance for credit losses, beginning of period	$ 13	$ 124
Bad debt expense	44	188
Write-offs, net of recoveries	0	(94)
Change in deferred interest on short-term and long-term installment receivables	67	56
Deferred interest and allowance for credit losses, end of period	$ 124	$ 274