Earnings Per Share (Calculation Of Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Earnings Per Share [Abstract]
Net Income (Loss) Available to Common Stockholders, Basic	$ 729.7	$ 465.7	$ 322.5
Dilutive Securities, Effect on Basic Earnings Per Share	0	0	0
Net Income (Loss) Available to Common Stockholders, Diluted	$ 729.7	$ 465.7	$ 322.5
Weighted Average Number of Shares Outstanding, Basic (in shares)	462.9	460.4	417.2
Dilutive effect on share-based awards (in shares)	1.8	2.8	6.4
Weighted Average Number of Shares Outstanding, Diluted (in shares)	464.7	463.2	423.6
Earnings Per Share, Basic (in dollars per share)	$ 1.58	$ 1.01	$ 0.77
Earnings Per Share, Diluted (in dollars per share)	$ 1.57	$ 1.01	$ 0.76