Financial Instruments, Derivatives and Hedging Activities (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Long-term debt
Carrying amount	$ 1,717	$ 1,724
Fair value	1,813	1,914
Carrying amount of fair value adjustment related to hedged fixed rate debt	13	20
Fair value adjustment related to hedged fixed rate debt	13	20
4.625% senior notes, due November 1, 2020
Long-term debt
Debt, fixed interest rate (as a percent)	4.625%	4.625%
Carrying amount	399	399
Fair value	420	448
3.2% senior notes, due November 1, 2015
Long-term debt
Debt, fixed interest rate (as a percent)	3.20%	3.20%
Carrying amount	350	350
Fair value	363	368
1.8% senior notes, due September 25, 2017
Long-term debt
Debt, fixed interest rate (as a percent)	1.80%	1.80%
Carrying amount	298	298
Fair value	296	300
6.625% senior notes, due April 15, 2037
Long-term debt
Debt, fixed interest rate (as a percent)	6.625%	6.625%
Carrying amount	257	257
Fair value	281	315
6.0% senior notes, due April 15, 2017
Long-term debt
Debt, fixed interest rate (as a percent)	6.00%	6.00%
Carrying amount	200	200
Fair value	219	227
5.62% senior notes due March 25, 2020
Long-term debt
Debt, fixed interest rate (as a percent)	5.62%	5.62%
Carrying amount	200	200
Fair value	$ 221	$ 236