Intangible Assets (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization expense		$ 7	$ 6	$ 14	$ 12
Finite-lived intangible assets, future amortization expense, four year estimate, minimum				23
Finite-lived intangible assets, future amortization expense, four year estimate, maximum				$ 28
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives				1 year
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Estimated useful lives				20 years
Cell Marque [Member]
Finite-Lived Intangible Assets [Line Items]
Cash consideration	$ 170