Retirement Benefits (Fair Value Disclosures) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan, Percentage of Global Investments in Plan Assets	75.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	$ 1,943.7	$ 1,918.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,918.7	1,879.6
Defined Benefit Plan, Business Combinations and Acquisitions, Plan Assets	0.0	0.0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	9,995.6	9,835.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	9,835.7	9,481.7
Defined Benefit Plan, Business Combinations and Acquisitions, Plan Assets	$ 235.9	0.0
Fixed Income Funds [Member]
Defined Benefit Plan, Target Allocation Percentage of Assets	20.00%
Fixed Income Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	$ 61.3	61.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	61.8
Fixed Income Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,316.6	1,230.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,230.7
Equity Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	104.5	92.3
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	92.3
Equity Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,221.3	1,146.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 1,146.6
Equity Securities [Member]
Defined Benefit Plan, Target Allocation Percentage of Assets	80.00%
Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	$ 40.0	39.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	39.2
Equity Securities [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	414.8	411.4
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	411.4
Equity Securities - International [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	144.7	158.9
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	158.9
Equity Securities - International [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	2,340.6	2,337.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	2,337.8
Fixed Income Funds, Emerging Markets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	36.9	35.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	35.5
Fixed Income Funds, Emerging Markets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	385.7	374.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	374.7
Hedge Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	272.3	282.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	282.7
Hedge Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	3,073.3	3,277.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	3,277.6
Real Estate [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	33.2	39.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	39.0
Real Estate [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	516.3	569.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	569.0
Other Assets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	41.1	20.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	20.1
Other Assets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	727.0	487.9
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	487.9
Other Contract [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,209.7	1,189.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,189.2
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	127.9	122.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	122.6
Fair Value, Inputs, Level 1 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	2,104.5	1,937.3
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,937.3
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	175.7	112.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	112.2
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	18.2	17.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	17.2
Fair Value, Inputs, Level 1 [Member] | Equity Securities [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	187.1	183.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	183.8
Fair Value, Inputs, Level 1 [Member] | Equity Securities - International [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	51.5	58.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	58.8
Fair Value, Inputs, Level 1 [Member] | Equity Securities - International [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	956.3	999.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	999.7
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds, Emerging Markets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Fixed Income Funds, Emerging Markets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	10.1	8.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	8.7
Fair Value, Inputs, Level 1 [Member] | Hedge Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Hedge Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	14.5	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 1 [Member] | Real Estate [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	33.2	39.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	39.0
Fair Value, Inputs, Level 1 [Member] | Real Estate [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	329.5	403.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	403.1
Fair Value, Inputs, Level 1 [Member] | Other Assets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	25.0	7.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	7.6
Fair Value, Inputs, Level 1 [Member] | Other Assets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	431.3	229.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	229.8
Fair Value, Inputs, Level 1 [Member] | Other Contract [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,587.7	1,579.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,579.6
Fair Value, Inputs, Level 2 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	5,040.0	5,076.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	5,076.2
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	61.3	61.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	61.8
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,140.9	1,118.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,118.5
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	67.4	75.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	75.2
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	21.8	22.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	22.0
Fair Value, Inputs, Level 2 [Member] | Equity Securities [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	227.7	227.6
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	227.6
Fair Value, Inputs, Level 2 [Member] | Equity Securities - International [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	93.2	100.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	100.1
Fair Value, Inputs, Level 2 [Member] | Equity Securities - International [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,384.3	1,338.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,338.1
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds, Emerging Markets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	36.9	35.3
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	35.3
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds, Emerging Markets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	375.3	364.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	364.2
Fair Value, Inputs, Level 2 [Member] | Hedge Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	148.7	158.7
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	158.7
Fair Value, Inputs, Level 2 [Member] | Hedge Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,537.9	1,694.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,694.5
Fair Value, Inputs, Level 2 [Member] | Real Estate [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 2 [Member] | Real Estate [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	10.8	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 2 [Member] | Other Assets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	16.1	12.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	12.5
Fair Value, Inputs, Level 2 [Member] | Other Assets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	295.7	258.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	258.1
Fair Value, Inputs, Level 2 [Member] | Other Contract [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,209.7	1,189.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,189.2
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	228.1	216.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	216.5	211.1
Defined Benefit Plan, Actual Return on Plan Assets Still Held	25.0	7.1
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	(11.2)	(0.1)
Defined Benefit Plan, Purchases, Sales, and Settlements	(2.0)	(0.5)
Defined Benefit Plan, Transfers Between Measurement Levels	(0.2)	(1.1)
Fair Value, Inputs, Level 3 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	2,851.1	2,822.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	2,822.2	2,603.2
Defined Benefit Plan, Actual Return on Plan Assets Still Held	161.5	152.7
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	(111.5)	(0.8)
Defined Benefit Plan, Purchases, Sales, and Settlements	(20.0)	78.5
Defined Benefit Plan, Transfers Between Measurement Levels	(1.1)	(11.4)
Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0	1.6
Defined Benefit Plan, Actual Return on Plan Assets Still Held		(0.1)
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period		(0.1)
Defined Benefit Plan, Purchases, Sales, and Settlements		(0.3)
Defined Benefit Plan, Transfers Between Measurement Levels		(1.1)
Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0	15.9
Defined Benefit Plan, Actual Return on Plan Assets Still Held		(0.4)
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period		(0.8)
Defined Benefit Plan, Purchases, Sales, and Settlements		(3.3)
Defined Benefit Plan, Transfers Between Measurement Levels		(11.4)
Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	104.5	92.3
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	92.3	88.9
Defined Benefit Plan, Actual Return on Plan Assets Still Held	10.3	6.0
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	1.9	(2.6)
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,153.9	1,071.4
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,071.4	993.5
Defined Benefit Plan, Actual Return on Plan Assets Still Held	78.3	108.2
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	4.2	(30.3)
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Equity Securities [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Equity Securities - International [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Equity Securities - International [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds, Emerging Markets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.2
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.2	0.0
Defined Benefit Plan, Actual Return on Plan Assets Still Held	0.0	0.0
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	0.0	0.2
Defined Benefit Plan, Transfers Between Measurement Levels	(0.2)	0.0
Fair Value, Inputs, Level 3 [Member] | Fixed Income Funds, Emerging Markets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.3	1.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1.8	0.0
Defined Benefit Plan, Actual Return on Plan Assets Still Held	(0.1)	0.1
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	(0.3)	1.7
Defined Benefit Plan, Transfers Between Measurement Levels	(1.1)	0.0
Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	123.6	124.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	124.0	120.6
Defined Benefit Plan, Actual Return on Plan Assets Still Held	14.7	1.2
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	(11.2)	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	(3.9)	2.2
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,520.9	1,583.1
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,583.1	1,440.4
Defined Benefit Plan, Actual Return on Plan Assets Still Held	89.4	44.6
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	(111.5)	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	(40.1)	98.1
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0	0.0
Defined Benefit Plan, Actual Return on Plan Assets Still Held	0.0	0.0
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	0.0	0.0
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	176.0	165.9
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	165.9	153.4
Defined Benefit Plan, Actual Return on Plan Assets Still Held	(6.1)	0.2
Defined Benefit Plan, Actual Return on Plan Assets Sold During Period	0.0	0.0
Defined Benefit Plan, Purchases, Sales, and Settlements	16.2	12.3
Defined Benefit Plan, Transfers Between Measurement Levels	0.0	0.0
Fair Value, Inputs, Level 3 [Member] | Other Assets [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Other Assets [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Fair Value, Inputs, Level 3 [Member] | Other Contract [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	$ 0.0
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 0.0