Common Equity 2 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
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	6,433,313		6,433,313
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 32.41		$ 32.41
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	3,800,683		3,800,683
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 26.10		$ 26.10
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term			4 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 4.7	$ 2.0	$ 14.6	$ 15.9
Proceeds from Stock Options Exercised			11.7	16.2
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			$ 5.9	$ 6.5
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	6,607,682		6,450,277
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0		495,550	864,860
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	$ 0.00		$ 52.90
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(174,369)		(512,514)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	6,433,313		6,433,313
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 32.11		$ 30.07
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	21.07		22.82
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 32.41		$ 32.41
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period			5 years 8 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 80.8		$ 80.8
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	3,800,683		3,800,683
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 26.10		$ 26.10
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term			4 years
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$ 71.7		$ 71.7