Related Party Transactions Related Party Transactions - Brightstar (Details) (Successor [Member], Brightstar [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2014		Sep. 30, 2014		Mar. 31, 2014
Successor [Member] | Brightstar [Member]
Related Party Transaction [Line Items]
Accounts receivable	$ 118		$ 118		$ 0
Accounts payable	7		7		0
Revenue from Related Parties	102	[1]	119	[1]
Related Party Costs	$ 78	[1]	$ 94	[1]

[1] (1)Amounts for the all other reported periods were immaterial.