Benefits (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Amounts recognized in Consolidated Balance Sheets
Other long-term liabilities	$ 222,700,000	$ 353,200,000
Information for pension plans with an accumulated benefit obligation in excess of fair value of assets
Accumulated benefit obligation	1,329,400,000	1,222,500,000
Pension Plans [Member]
Change in Plan Assets
Fair Value at January 1	1,059,500,000	1,026,000,000
Actual earnings (loss) on plan assets	33,800,000	110,100,000
Employer contributions	242,900,000	6,800,000
Participants' contributions	0	0
Gross benefits paid	(73,700,000)	(83,400,000)
Fair Value at December 31	1,262,500,000	1,059,500,000
Amounts recognized in Consolidated Balance Sheets
Other deferred charges	0	0
Other long-term liabilities	68,100,000	163,300,000
Net Liability	68,100,000	163,300,000
Amounts not yet been recognized in net periodic benefit cost
Net actuarial loss	633,400,000	521,000,000
Prior service costs (credits)	14,400,000	16,700,000
Transition obligation	0	0
Total	647,800,000	537,700,000
OPEB [Member]
Change in Plan Assets
Fair Value at January 1	216,700,000	202,600,000
Actual earnings (loss) on plan assets	9,000,000	24,500,000
Employer contributions	48,400,000	4,900,000	24,300,000
Participants' contributions	11,600,000	6,500,000
Gross benefits paid	(30,300,000)	(21,800,000)
Fair Value at December 31	255,400,000	216,700,000	202,600,000
Amounts recognized in Consolidated Balance Sheets
Other deferred charges	20,300,000	38,300,000
Other long-term liabilities	154,600,000	189,900,000
Net Liability	134,300,000	151,600,000
Amounts not yet been recognized in net periodic benefit cost
Net actuarial loss	108,100,000	98,900,000
Prior service costs (credits)	(6,100,000)	(8,500,000)
Transition obligation	300,000	600,000
Total	$ 102,300,000	$ 91,000,000