Benefits (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Matching contributions under Savings Plans	$ 14,200,000	$ 13,800,000	$ 14,100,000
A one-percentage-point change in assumed health care cost trend rates effects
1% Increase, in assumed health care cost trend rates, Effect on, Post-retirement benefit obligation	26,400,000
1% Decrease, in assumed health care cost trend rates, Effect on, Post-retirement benefit obligation	(22,300,000)
1% Increase, in assumed health care cost trend rates, Effect on, Total of service and interest cost components	3,200,000
1% Decrease, in assumed health care cost trend rates, Effect on, Total of service and interest cost components	(2,600,000)
Benefits (Textuals) [Abstract]
Health care cost trend rate up to specified age	65
Health care cost trend rate post specified age	65
Current pension plan target asset allocation in equity investments	45.00%
Current pension plan target asset allocation in fixed income investments	55.00%
Other Post-Retirement Employee Benefits target asset allocation in equity investments	60.00%
Other Post-Retirement Employee Benefits target asset allocation in fixed income investments	40.00%
Matching contributions under Savings Plans	14,200,000	13,800,000	14,100,000
Postemployment benefits liability	4,200,000	4,000,000
Pension, Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded Status of Plan	138,700,000	(20,900,000)
Pension, Non-Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded Status of Plan	(97,900,000)	(102,200,000)
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	1,410,200,000	1,508,500,000	1,330,600,000
Defined Benefit Plan, Amortization of Previously Unrecognized Benefit Costs	38,700,000
Net Periodic Benefit Cost
Service cost	14,600,000	21,700,000	15,900,000
Interest cost	60,400,000	65,500,000	67,600,000
Expected return on plan assets	(95,800,000)	(89,600,000)	(82,100,000)
Amortization of:
Transition obligation	0	0	0
Prior service cost (credit)	2,300,000	2,200,000	2,200,000
Actuarial loss	54,500,000	41,000,000	34,000,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	2,500,000	0	0
Curtailment (gain)	0	400,000	0
Net Periodic Benefit Cost	38,500,000	41,200,000	37,600,000
Weighted-Average assumptions used to determine benefit obligations as of Dec. 31
Discount rate	5.00%	4.10%	5.05%
Rate of compensation increase	4.00%	4.00%	4.00%
Weighted-Average assumptions used to determine net cost for year ended Dec. 31
Discount rate	4.10%	5.05%	5.60%
Expected return on plan assets	7.25%	7.25%	7.25%
Rate of compensation increase	4.00%	4.00%	4.00%
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	1,451,000,000	1,385,400,000	1,262,500,000
Employer contributions to defined benefit plan
Employer contributions	8,700,000	102,700,000
Expected benefit payments in future
2012	103,900,000
2013	98,600,000
2014	100,300,000
2015	100,900,000
2016	100,200,000
2017-2021	495,600,000
Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	873,200,000	763,100,000
Pension Plans [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	577,800,000	622,300,000
Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | Cash And Cash Equivalents [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	21,000,000	13,700,000
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	21,000,000	13,700,000
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | U.S. Equity [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	519,500,000	466,300,000
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	519,500,000	466,300,000
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | International Equity [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	181,900,000	165,100,000
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	146,200,000	134,700,000
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	35,700,000	30,400,000
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | U.S. Bonds [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	613,600,000	614,300,000
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	108,400,000	67,700,000
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	505,200,000	546,600,000
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension Plans [Member] | International Bonds [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	115,000,000	126,000,000
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	78,100,000	80,700,000
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	36,900,000	45,300,000
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	362,700,000	381,200,000	389,700,000
Defined Benefit Plan, Amortization of Previously Unrecognized Benefit Costs	(900,000)
Net Periodic Benefit Cost
Service cost	10,000,000	10,300,000	10,400,000
Interest cost	15,600,000	20,300,000	20,800,000
Expected return on plan assets	(21,300,000)	(19,000,000)	(16,900,000)
Amortization of:
Transition obligation	0	300,000	300,000
Prior service cost (credit)	(2,000,000)	(1,900,000)	(1,900,000)
Actuarial loss	3,700,000	7,300,000	6,200,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	0	0	0
Curtailment (gain)	0	0	0
Net Periodic Benefit Cost	6,000,000	17,300,000	18,900,000
Weighted-Average assumptions used to determine benefit obligations as of Dec. 31
Discount rate	4.95%	4.15%	5.20%
Weighted-Average assumptions used to determine net cost for year ended Dec. 31
Discount rate	4.15%	5.20%	5.70%
Expected return on plan assets	7.50%	7.50%	7.50%
Assumed health care cost trend rates as of Dec. 31
Health care cost trend rate assumed for next year, Pre 65	0.0750	0.0750	0.0800
Health care cost trend rate assumed for next year, Post 65	0.0750	0.0750	0.1200
Rate that the cost trend rate gradually adjusts to	0.050	0.050	0.050
Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65)	2021/2021	2017/2017	2017/2017
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	327,600,000	285,400,000	255,400,000
Employer contributions to defined benefit plan
Employer contributions	14,100,000	17,700,000	48,400,000
Expected benefit payments in future
2012	24,200,000
2013	21,600,000
2014	22,000,000
2015	22,600,000
2016	23,400,000
2017-2021	119,700,000
OPEB [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	222,700,000	187,900,000
OPEB [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	104,900,000	97,500,000
OPEB [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | Cash And Cash Equivalents [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	2,600,000	1,700,000
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	2,600,000	1,700,000
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | U.S. Equity [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	148,000,000	125,900,000
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	148,000,000	125,900,000
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | International Equity [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	49,700,000	42,100,000
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	46,900,000	39,900,000
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	2,800,000	2,200,000
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | U.S. Bonds [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	104,700,000	94,900,000
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	8,400,000	5,000,000
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	96,300,000	89,900,000
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
OPEB [Member] | International Bonds [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	22,600,000	20,800,000
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	16,800,000	15,400,000
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	5,800,000	5,400,000
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Summary of fair value of pension plan assets by asset category within the fair value hierarchy
Fair value of our pension plan assets	0	0
Pension, Qualified [Member] | Pension Plans [Member]
Employer contributions to defined benefit plan
Employer contributions	0	95,600,000	236,400,000
Pension, Non-Qualified [Member] | Pension Plans [Member]
Employer contributions to defined benefit plan
Employer contributions	$ 8,700,000	$ 7,100,000	$ 6,500,000