Severance and Exit Costs (Details) - USD ($) $ in Millions		3 Months Ended
		Jun. 30, 2016	Jun. 30, 2015
Restructuring Cost and Reserve [Line Items]
Severance Costs	[1]	$ 4
Restructuring Charges		$ 18
Other Operating Income (Expense) [Member] | Wireless [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment			$ 41

[1] For the three-month period ended June 30, 2016, we recognized costs of $4 million (Wireless only).