Common Stock (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended				12 Months Ended				12 Months Ended						12 Months Ended			3 Months Ended				12 Months Ended
	Nov. 30, 2009	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	May 31, 2011	Dec. 31, 2011 Minimum [Member]	Dec. 31, 2011 Maximum [Member]	Dec. 31, 1999 Supplemental Stock Ownership Plan [Member]	Mar. 12, 2002 2002 Long-Term Incentive Plan [Member]	Dec. 31, 2011 2006 Long-Term Incentive Plan [Member]	May 13, 2009 2006 Long-Term Incentive Plan [Member]	Dec. 31, 2011 Stock Option [Member] Y	Dec. 31, 2010 Stock Option [Member]	Dec. 31, 2009 Stock Option [Member]	Dec. 31, 2011 Restricted Stock [Member]	Sep. 30, 2011 Restricted Stock [Member]	Jun. 30, 2011 Restricted Stock [Member]	Mar. 31, 2011 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member] Y	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2009 Restricted Stock [Member]	Dec. 31, 2011 Restricted stock, restricted stock units, long term performance units, SARs [Member] Y	Dec. 31, 2010 Restricted stock, restricted stock units, long term performance units, SARs [Member]	Dec. 31, 2009 Restricted stock, restricted stock units, long term performance units, SARs [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Treasury stock shares		1,694,692				1,694,692	1,294,692
Authorized treasury shares available for purchase under the supplemental stock ownership plan												1,100,000
Authorized common stock available for issuance under the plan		135,000,000				135,000,000							4,000,000	1,569,025	2,300,000
Term for stock options										P7Y	P20Y
Restriction period for restricted common stock																3 years							3 years
Compensation expense related to nonqualified stock options						$ 3	$ 3	$ 3
Decrease in basic and diluted earnings per share.						$ 0.05	$ 0.05	$ 0.06
Share based compensation						8	9	7																		11	14	5
Share-based Compensation, Aggregate Disclosure
Count of each share from a stock option award against shares available for issuance under the plan															1
Count of each share from a full value award against shares available for issuance under the plan															1.25
Unrecognized compensation costs																5			5				5			7
Unrecognized compensation costs, weighted average period																0.7							1.8			1.2
Cash received from stock option exercises																6	6	1
Unrecorded tax benefit from stock options exercised																4	4	1
Weighted average grant-date fair value of options granted						$ 45.37	$ 11.84	$ 1.34
Total Intrinsic value of options exercised		3	3	3	3	13	10	4
Total fair value of shares vested		3				3	3	4
Total fair value of restricted shares vested																							3	2	2
Weighted average grant-date fair value of restricted stock granted						$ 45.38	$ 19.60	$ 2.02											$ 24.97	$ 44.02	$ 43.51	$ 45.42
Common Stock (Textual) [Abstract]
Common Stock, Par value		$ 0.01				$ 0.01
Shares of common stock issued		62,101,335				62,101,335	61,541,760
Public offering, common stock	12,000,000
Public offering, Common Stock, price	$ 16.50
Public offering, gross proceeds	198
Public offering, net proceeds	188							188
2012 authorized outstanding common stock for repurchase over a 12 month period		600,000				600,000			400,000
Stock repurchase duration in 2012						12 months
Repurchased stock						400,000
Payment for treasury shares						$ 16