Credit Facilities and Debt (Summary of Debt Outstanding) (Details) - USD ($) $ in Millions		Sep. 30, 2016		Dec. 31, 2015		Sep. 20, 2011
Credit Facilities and Long-Term Debt :
Debt issuance costs and unamortized discount		$ (12)		$ (4)
Long-term debt		1,148		1,196
Total debt		1,210		1,274
Commercial Paper, at Carrying Value		20		0
Commercial Paper		600
Other		0		2
Short-term borrowings and current maturities of long-term debt		62		78
Senior Notes Due 2016, 3.550%
Credit Facilities and Long-Term Debt :
Senior Notes Due		0	[1]	600	[1]	$ 600
Senior Notes Due 2021, 4.875%
Credit Facilities and Long-Term Debt :
Senior Notes Due		600	[1]	600	[1]	$ 600
Senior Notes Due 2023, 2.250%
Credit Facilities and Long-Term Debt :
Senior Notes Due	[1]	560		0
Risk Sharing Finance Facility Agreement
Credit Facilities and Long-Term Debt :
Research and development facility agreement		$ 42		$ 76

[1] The fair value of our Senior Notes (as defined below) was determined using quoted prices in active markets for identical securities, which are considered Level 1 inputs. The fair value of our Senior Notes due 2021 was $654 million and $640 million as of September 30, 2016 and December 31, 2015, respectively. The fair value of our Senior Notes due 2023 was $608 million as of September 30, 2016.