Common Equity Common Equity 2 (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
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	8,276,994
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 28.82
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,337,979
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 23.80
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 15.3	$ 24.4
Exercise of stock options	15.2	27.3
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	6.1	9.7
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	8,089,710
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	899,500	1,418,560
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	$ 41.03
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(705,831)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	(6,385)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	8,276,994
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 26.84
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	$ 30.47
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 36.55
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 28.82
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period	5 years 10 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	146.7
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,337,979
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 23.80
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4 years 1 month
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$ 121.5