Pension and Postretirement Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	$ 6.4	$ 4.8	$ 3.6
Fair value of plan assets	324.6	336.3
Capitalized portion of defined benefit contribution percent	7.00%	8.00%	10.00%
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Total	208.8	160.0
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Pension and postretirement benefit obligations (noncurrent liablity)	389.9	333.1
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Target allocation percentage of assets, equity securities	61.00%
Target Allocation Percentage of Assets, Debt Securities	33.00%
Target Allocation Percentage of Assets, Real Estate	6.00%
Allocation Percentage in US based Investments	75.00%
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Special termination benefit		0	2.1
Curtailment loss (gain)	4.2	0	(7.6)
Disclosure of Expected Gross Prescription Drug Subsidy Receipts [Abstract]
2012	0.7
2013	0.7
2014	0.7
2015	0.7
2016	0.6
Years 2017-2021	2.6
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	312.5	324.0	325.4
Pension and Other Postretirement Benefit Contributions [Abstract]
Employer contributions	20.1	7.7
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements [Abstract]
Balance, beginning of the year	21.1	19.6
Realized gains, net	1.7	1.3
Unrealized gains, net	3.1	1.3
Purchases, sales, issuances, settlements	(0.4)	(1.1)
Balance, end of the year	25.5	21.1	19.6
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service benefit (cost), net of tax $0.2, $1.9, $(30.8), $(36.2)	(0.4)	(3.3)
Actuarial loss, net of tax $111.6, $90.5, $37.3, $25.5	(196.8)	(157.9)
Total	(197.2)	(161.2)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Tax Effect	0.2	1.9
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	111.6	90.5
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	3.90%	4.90%
Future compensation growth rate	3.00%	3.50%
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued payroll and benefits (current liability)	1.7	1.9
Pension and postretirement benefit obligations (noncurrent liablity)	255.0	200.2
Total	256.7	202.1
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5.1	5.2	5.7
Interest cost on projected benefit obligation	24.8	26.8	29.0
Expected Return on Plan Assets	(29.3)	(30.3)	(26.0)
Transition obligation	0	0	0
Amortization of: Prior service cost (benefit)	0.3	0.5	0.7
Amortization of: Actuarial loss	14.3	9.3	8.7
Special termination benefit	0	0	1.8
Curtailment loss (gain)	4.2	0	(7.6)
Benefit costs	19.4	11.5	12.3
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2012	43.2
2013	39.9
2014	41.6
2015	40.9
2016	42.1
Years 2017-2021	201.4
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12.1	12.3	20.9
Pension and Other Postretirement Benefit Contributions [Abstract]
Employer contributions	24.1	17.7
Estimated Future Employer Contributions in Next Fiscal Year	21.6
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, Sales, Issuances, Settlements [Abstract]
Balance, beginning of the year	12.3	0
Realized gains, net	0.3	0
Unrealized gains, net	0	0
Purchases, sales, issuances, settlements	(0.5)	12.3
Balance, end of the year	12.1	12.3	0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Prior service benefit (cost), net of tax $0.2, $1.9, $(30.8), $(36.2)	54.3	62.0
Actuarial loss, net of tax $111.6, $90.5, $37.3, $25.5	(65.9)	(60.8)
Total	(11.6)	1.2
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Tax Effect	(30.8)	(36.2)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), Tax Effect	37.3	35.5
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate	3.60%	4.50%
Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract]
Accrued payroll and benefits (current liability)	21.5	22.1
Pension and postretirement benefit obligations (noncurrent liablity)	131.3	129.1
Total	152.8	151.2
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.3	0.2	0.4
Interest cost on projected benefit obligation	7.1	8.0	10.3
Expected Return on Plan Assets	0	0	(0.9)
Transition obligation	0	0	0.1
Amortization of: Prior service cost (benefit)	(13.2)	(13.1)	(12.1)
Amortization of: Actuarial loss	6.5	5.2	4.5
Special termination benefit	0		0.3
Curtailment loss (gain)	0	0	0
Benefit costs	0.7	0.3	2.6
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2012	22.3
2013	21.3
2014	16.7
2015	17.1
2016	16.3
Years 2017-2021	54.8
pension plan qualified [Member]
Pension and Other Postretirement Benefit Contributions [Abstract]
Estimated Future Employer Contributions in Next Fiscal Year	30.0
Pension benefit contributions	18.1	5.6	50.0
Pension Plan Non-Qualified [Member]
Pension and Other Postretirement Benefit Contributions [Abstract]
Estimated Future Employer Contributions in Next Fiscal Year	2.1
Pension benefit contributions	2.0	2.1	2.2
Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	150.6	159.2
Equity Index Funds International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.2	46.1
Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91.9	96.5
Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.3	1.1
Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25.5	21.1
Insurance Contract, Rights and Obligations, Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12.1	12.3
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	286.7	301.8
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	150.6	159.2
Fair Value, Inputs, Level 1 [Member] | Equity Index Funds International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	44.2	46.1
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91.9	96.5
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 1 [Member] | Insurance Contract, Rights and Obligations, Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.3	1.1
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Equity Index Funds International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0.3	1.1
Fair Value, Inputs, Level 2 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 2 [Member] | Insurance Contract, Rights and Obligations, Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	37.6	33.4
Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | Equity Index Funds International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Fair Value, Inputs, Level 3 [Member] | Real Estate Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	25.5	21.1
Fair Value, Inputs, Level 3 [Member] | Insurance Contract, Rights and Obligations, Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 12.1	$ 12.3