Common Equity Common Equity 2 (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	9,571,531		9,571,531
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 23.42		$ 23.42
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	7,845,366		7,845,366
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 21.76		$ 21.76
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term			4 years 11 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 21.6	$ 9.9	$ 33.6	$ 19.0
Proceeds from Stock Options Exercised			38.6	29.6
Tax Benefit from Stock Options Exercised			0	7.5
Stock options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	10,851,131		10,638,750
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0		938,770	458,180
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	$ 0.00		$ 34.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(1,279,600)		(1,998,269)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	0		(7,720)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	9,571,531		9,571,531
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 23.03		$ 21.65
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	$ 20.09		$ 19.34
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 0.00		$ 26.94
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 23.42		$ 23.42
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period			5 years 7 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	154.5		154.5
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	7,845,366		7,845,366
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 21.76		$ 21.76
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term			4 years 11 months
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$ 139.7		$ 139.7