Stock Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended						8 Months Ended	12 Months Ended																	8 Months Ended		12 Months Ended			8 Months Ended		12 Months Ended			8 Months Ended	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2013 2013 Performance Units Grants [Member]	Dec. 31, 2013 Performance Units Related to Earnings Per Share [Member]		Dec. 31, 2012 Performance Units Related to Earnings Per Share [Member]	Dec. 31, 2011 Performance Units Related to Earnings Per Share [Member]	Dec. 31, 2013 Total Shareholder Return [Member]		Dec. 31, 2012 Total Shareholder Return [Member]	Dec. 31, 2011 Total Shareholder Return [Member]	Dec. 31, 2013 Performance Shares [Member]	Dec. 31, 2012 Performance Shares [Member]	Dec. 31, 2011 Performance Shares [Member]	Dec. 31, 2013 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2013 Stock Compensation Plan [Member]	Dec. 31, 2012 Stock Compensation Plan [Member]	Dec. 31, 2011 Stock Compensation Plan [Member]	Dec. 31, 2013 2012 Performance Unit Grants [Member]	Dec. 31, 2013 Performance Units Related to Earnings Per Share [Member] 2013 Performance Units Grants [Member]	Dec. 31, 2013 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2012 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2011 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2013 Performance Units Related to Earnings Per Share [Member] 2012 Performance Unit Grants [Member]	Dec. 31, 2013 Total Shareholder Return [Member] 2013 Performance Units Grants [Member]	Dec. 31, 2013 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2012 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2011 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2013 Total Shareholder Return [Member] 2012 Performance Unit Grants [Member]	Dec. 31, 2013 Common Stock [Member]	Dec. 31, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Dec. 31, 2013 Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number								354,026		327,838		1,062,060		1,069,128					23,628	49,106
Number of Shares Authorized	7,400,000
Compensation Expense																$ 10.7	$ 12.2	$ 13.7	$ 0.4	$ 0.6	$ 1.0	$ 11.1	$ 12.8	$ 14.7			$ 2.3	$ 4.2	$ 5.5			$ 8.4	$ 8.0	$ 8.2
Amount paid by unconsolidated affiliates																						3.1	0	0
Compensation Expense, Net of Unconsolidated Affiliates																						8.0	12.8	14.7
Tax Benefit from Compensation Expense	3.1		4.9		5.7
Shares Issued in Period																																				548,344	849,110	623,246
Shares Paid for Tax Withholding																																							11,318
Equity Instruments Other than Options, Grants in Period							91,390	74,570	[1]	81,594	142,476	316,162	[1]	338,678	427,442				5,940	10,824	35,804				82,930	45,794				41,376	45,596				41,554
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value								$ 26.73		$ 23.82	$ 20.81	$ 25.89		$ 25.91	$ 23.05				$ 29.71	$ 26.72	$ 24.41					$ 26.73				$ 34.94	$ 25.89				$ 47.71
Expected Dividend Rate												2.80%		3.00%	3.20%
Expected Volatility Rate												20.00%		22.00%	33.00%
Risk Free Interest Rate												0.37%		0.38%	1.40%
Expected Term												2 years 10 months 2 days		2 years 10 months 13 days	2 years 10 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Equity Instruments Other Than Options, Modification								87,170	[2]			87,150	[2]
Equity Instruments Other than Options, Converted in Period								(125,760)	[3]			(377,266)	[3]
Equity Instruments Other than Options, Vested in Period								(118,350)				(355,078)							(30,242)
Equity Instruments Other than Options, Forfeited in Period								(9,792)				(33,114)							(1,176)
Awards Other than Options, Fully Vested								118,350				355,078
Equity Instruments Other than Options, Converted, Aggregrate Intrinsic Value								7.4	[2]			22.1	[2]
Equity Instruments Other than Options, Vested in Period, Aggregate Intrinsic Value																			0.9
Equity Instruments Other than Options, Outstanding, Aggregrate Intrinsic Value								13.9				50.9							0.8
Equity Instruments Other than Options, Fully Vested, Aggregrate Intrinsic Value								8.0				19.3
Minimum payout range	0.00%
Maximum payout range	200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Equity Instruments Other than Options, Nonvested, Number, Beginning Balance								202,078				691,862							49,106
Equity Instruments Other Than Options, Modification								87,170	[2]			87,150	[2]
Equity Instruments Other than Options, Vested in Period								(118,350)				(355,078)							(30,242)
Equity Instruments Other than Options, Nonvested, Number, Ending Balance								235,676		202,078		706,982		691,862					23,628	49,106
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value								$ 25.28		$ 22.00		$ 25.90		$ 24.40					$ 26.30	$ 23.61
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value								$ 26.73		$ 23.82	$ 20.81	$ 25.89		$ 25.91	$ 23.05				$ 29.71	$ 26.72	$ 24.41					$ 26.73				$ 34.94	$ 25.89				$ 47.71
Equity Instruments Other than Options, Modifications in Period, Weighted Average Grant Date Fair Value								$ 30.62				$ 36.29
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value								$ 20.81				$ 23.05							$ 22.57
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value								$ 23.34				$ 24.96							$ 26.87
Awards Other than Options, Vested and Expected to Vest, Outstanding								209,938	[4]			633,808	[4]						23,628
Equity Instruments Other than Options, Expected to Vest, Intrinsic Value								5.6				28.3
Fair Value of Vested Performance Units and Restricted Stock								4.9		4.1	3.9	8.2		7.4	7.4				0.7	0.7	1.0
Total Compensation Cost Not yet Recognized	10.4							1.8				8.4				10.2			0.2
Total Compensation Cost Not yet Recognized, Period for Recognition								1 year 5 months 27 days				1 year 7 months 17 days							1 year 7 months 17 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding, Beginning Balance	39,200
Options, Exercises in Period	(39,200)
Options, Outstanding, Ending Balance	0		39,200
Options, Exercisable	0
Options, Outstanding, Weighted Average Exercise Price	$ 0.00		$ 11.40
Options, Exercises in Period, Weighted Average Exercise Price	$ (11.40)
Options, Exercisable, Weighted Average Exercise Price	$ 0.00
Options, Exercises in Period, Total Intrinsic Value	1.4	[5]	2.0	[5]	2.2	[5]
Options, Outstanding, Intrinsic Value	0
Options, Outstanding, Weighted Average Remaining Contractual Term	0 days
Options, Exercisable, Intrinsic Value	0
Options, Exercisable, Weighted Average Remaining Contractual Term	0 days
Options, Exercises in Period, Total Intrinsic Value	1.4	[5]	2.0	[5]	2.2	[5]
Cash Received from Exercise of Stock Options	$ 0.4		$ 0.8		$ 1.3

[1] For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.

[2] These amounts represent the performance unit grants previously based on earnings before interest, taxes, depreciation and amortization that were converted to performance units based on total shareholder return or earnings per share as a result of the formation of Enable.

[3] These amounts represent performance units that vested at December 31, 2012 which were settled in February 2013.

[4] The intrinsic value of the performance units based on total shareholder return and earnings per share is $28.3 million and $5.6 million, respectively.

[5] The difference between the market value on the date of exercise and the option exercise price.