Debt (Carrying Value Of Long-Term Debt Of Outstanding) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Senior notes, carrying amount	$ 1,623,000,000	$ 1,632,000,000
Other long-term borrowings	36,000,000	37,000,000
Total long-term debt	1,659,000,000	1,669,000,000
$500 Million, 6.45% Due June 1, 2016 [Member]
Debt Instrument [Line Items]
Senior notes	500,000,000
Senior note interest rate	6.45%
Senior notes, carrying amount	530,000,000	535,000,000
Debt instrument, maturity date	Jun. 01, 2016
$500 Million, 7.20% Due June 15, 2018 [Member]
Debt Instrument [Line Items]
Senior notes	500,000,000
Senior note interest rate	7.20%
Senior notes, carrying amount	507,000,000	508,000,000
Debt instrument, maturity date	Jun. 15, 2018
$300 Million, 6.30% due August 1, 2018 [Member]
Debt Instrument [Line Items]
Senior notes	300,000,000
Senior note interest rate	6.30%
Senior notes, carrying amount	319,000,000	322,000,000
Debt instrument, maturity date	Aug. 01, 2018
$250 Million, 8.15% Due June 15, 2038 [Member]
Debt Instrument [Line Items]
Senior notes	250,000,000
Senior note interest rate	8.15%
Senior notes, carrying amount	$ 267,000,000	$ 267,000,000
Debt instrument, maturity date	Jun. 15, 2038