Long-term Debt (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Summary of Other Long-Term Debt
Long-term debt, carrying amount	$ 5,732	$ 5,504
Fair value adjustment-hedging	13	13
Other Long-term Debt, Noncurrent, Total	5,745	5,517
4.50% Guaranteed Notes due 2014 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	1,437	1,319
2.75% Guaranteed Notes due 2015 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	1,428	1,310
4.200% Guaranteed Notes due 2021
Summary of Other Long-Term Debt
Long-term debt, carrying amount	1,099	0
5.25% Guaranteed Notes due 2013 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	718	659
2.65% Guaranteed Notes due 2016 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	497	0
9.75% Senior Notes due 2019 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	0	776
3.00% Guaranteed Notes due 2013 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	450	450
8.625% Senior Notes due 2014 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	0	272
6.00% Senior Notes due 2016 [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	0	218
Commercial Paper [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	0	367
Debt, Other [Member]
Summary of Other Long-Term Debt
Long-term debt, carrying amount	$ 103	$ 133