Income Taxes (Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Taxes [Abstract]
Adjustment of deferred tax balances	$ 11
Federal research and development credits	2	$ 4
Reversal of reserves for uncertain tax postions		1
Benefit resulting from state law changes		3
Domestic production activities deduction	7	$ 9
Deferred Tax Assets, Net, Current	$ 71		$ 97