Severance and Exit Costs (Details) $ in Millions	3 Months Ended
	Jun. 30, 2015 USD ($)
Lease and access exit costs [Member] | Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring And Related Cost Expected Future Cost	$ 75
Lease and access exit costs [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring And Related Cost Expected Future Cost	150
Other Operating Income (Expense) [Member] | Wireless [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve, Accrual Adjustment	$ 20