Antidilutive Shares (Details) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Antidilutive Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		16.2		55.1
Antidilutive Stock Options, Exercise Price Greater Than Average Market Price	8.9	[1]	15.6	[1]	21.2	[1]
Antidilutive Warrants Excluded Exercise Price Greater Than Average Market Price	0	[2]	0	[2]	67.9	[2]
4.75% Notes
Antidilutive Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		0		16.1
4.50% Notes
Antidilutive Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		0		0.6
Preferred stock outstanding
Antidilutive Securities
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		16.2		38.4

[1] These options are outstanding at the end of the respective periods. In any period in which the exercise price is less than the average market price, these options have the potential to be dilutive, and application of the treasury stock method would reduce this amount.

[2] The potential dilutive impact of the warrants is based upon the difference between the market price of one share of our common stock and the stated exercise prices of the warrants, adjusted to reflect the period during which the warrants were outstanding. The warrants expired in June 2009.