Benefits (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	$ 1,507,100,000	$ 1,329,400,000
Amounts recognized in Consolidated Balance Sheets
Other long-term liabilities	244,000,000	222,700,000
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	1,508,500,000	1,330,600,000	1,222,800,000
Change in Plan Assets
Fair Value at January 1	1,262,500,000	1,059,500,000
Actual earnings (loss) on plan assets	127,400,000	33,800,000
Employer contributions	102,700,000	242,900,000
Participants' contributions	0	0
Gross benefits paid	(107,200,000)	(73,700,000)
Fair Value at December 31	1,385,400,000	1,262,500,000
Amounts recognized in Consolidated Balance Sheets
Other deferred charges	0	0
Other long-term liabilities	123,100,000	68,100,000
Net Liability	123,100,000	68,100,000
Amounts not yet been recognized in net periodic benefit cost
Net actuarial loss	719,200,000	633,400,000
Prior service costs (credits)	12,200,000	14,400,000
Transition obligation	0	0
Total	731,400,000	647,800,000
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	381,200,000	389,700,000	368,300,000
Change in Plan Assets
Fair Value at January 1	255,400,000	216,700,000
Actual earnings (loss) on plan assets	29,000,000	9,000,000
Employer contributions	17,700,000	48,400,000	4,900,000
Participants' contributions	9,600,000	11,600,000
Gross benefits paid	(26,300,000)	(30,300,000)
Fair Value at December 31	285,400,000	255,400,000	216,700,000
Amounts recognized in Consolidated Balance Sheets
Other deferred charges	25,100,000	20,300,000
Other long-term liabilities	120,900,000	154,600,000
Net Liability	95,800,000	134,300,000
Amounts not yet been recognized in net periodic benefit cost
Net actuarial loss	65,300,000	108,100,000
Prior service costs (credits)	(3,700,000)	(6,100,000)
Transition obligation	0	300,000
Total	$ 61,600,000	$ 102,300,000