Financing (LYONs) (Narrative) (Details) (USD $)	12 Months Ended				132 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2001	Dec. 31, 2011	Jan. 22, 2011
Debt Instrument [Line Items]
Interest payments	$ 133,000,000	$ 107,000,000	$ 88,000,000
Liquid Yield Option Notes Due 2021 [Member]
Debt Instrument [Line Items]
Principal amount of debt issued				830,000,000
Net proceeds from borrowings				505,000,000
Repayment of debt				100,000,000
Interest rate of debt instrument				2.375%
Convertible portion of debt instrument				1,000
Number of shares converted to through one convertible bond				29.0704
Shares issued under debt conversion				24,000,000	10,000,000
Debt instrument maturity date	Jan. 22, 2021
Accreted value of exchangeable debt instrument						1,000,000
Average market price percentage for measurement period resulting in payment of contingent interest to debt instrument holders	120.00%				120.00%
Percentage of bonds' average market price	0.0315%
Interest payments	$ 1,000,000	$ 2,000,000	$ 1,000,000
2021 Notes [Member]
Debt Instrument [Line Items]
Interest rate of debt instrument	3.90%				3.90%
Debt instrument maturity date	Jun. 23, 2021
Percentage of notes' principal in addition to accrued interest that redemption price must equal or be greater than if a credit downgrade or change in control occurs	101.00%
Eurobond Notes [Member]
Debt Instrument [Line Items]
Interest rate of debt instrument	4.50%				4.50%
Percentage of notes' principal in addition to accrued interest that redemption price must equal or be greater than if a credit downgrade or change in control occurs	100.00%