Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Tax Reconciliation, Change in Deferred Tax Assets Valuation Allowance	$ 22	$ (27)
Decrease in valuation allowance attributable to disposition of intangible assets		73
Increase in valuation allowance attributable to operating loss carryforward		46
Income tax benefit	$ 17	15
FCC License Amortization Period for Tax Purposes In Years	15 years
Unrecognized tax benefit	$ 168		$ 163
Income Taxes Paid, Net	$ 26	$ 28