Retirement Benefits (Schedule of Benefit Obligations and Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	$ 0.0	$ 334.7
Defined Benefit Plan, Benefit Obligation, Beginning Balance	11,719.2	12,012.4
Defined Benefit Plan, Service Cost	277.7	315.7	$ 240.9
Defined Benefit Plan, Interest Cost	420.8	476.8	472.6
Defined Benefit Plan, Actuarial Net (Gains) Losses	806.5	(812.4)
Defined Benefit Plan, Benefits Paid	(454.5)	(437.8)
Defined Benefit Plan, Plan Amendments	0.0	(0.4)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(313.8)	(169.8)
Defined Benefit Plan, Benefit Obligation, Ending Balance	12,455.9	11,719.2	12,012.4
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	9,995.6	9,835.7
Defined Benefit Plan, Actual Return on Plan Assets	853.4	90.4
Defined Benefit Plan, Contributions by Employer	110.2	404.1
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	(325.0)	(132.7)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	10,179.7	9,995.6	9,835.7
Defined Benefit Plan, Funded Status of Plan	(2,276.2)	(1,723.6)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	4,915.7	4,552.7
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	21.7	32.5
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total	2,661.2	2,861.6
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Business Combinations and Acquisitions, Benefit Obligation	0.0	9.9
Defined Benefit Plan, Benefit Obligation, Beginning Balance	1,467.4	1,553.5
Defined Benefit Plan, Service Cost	39.1	45.1	33.0
Defined Benefit Plan, Interest Cost	53.2	62.6	85.6
Defined Benefit Plan, Actuarial Net (Gains) Losses	50.9	(113.5)
Defined Benefit Plan, Benefits Paid	(59.8)	(77.5)
Defined Benefit Plan, Plan Amendments	(35.8)	0.0
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(20.4)	(12.7)
Defined Benefit Plan, Benefit Obligation, Ending Balance	1,494.6	1,467.4	1,553.5
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,943.7	1,918.7
Defined Benefit Plan, Actual Return on Plan Assets	68.9	85.1
Defined Benefit Plan, Contributions by Employer	8.4	17.4
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	0.0	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,961.2	1,943.7	$ 1,918.7
Defined Benefit Plan, Funded Status of Plan	466.6	476.3
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	458.8	347.9
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(525.1)	(574.8)
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total	400.3	249.4
Fair Value, Inputs, Level 2 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	992.1
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,247.0	992.1
Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,276.9
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,288.6	1,276.9
Fair Value, Inputs, Level 3 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	17.1
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	17.1	17.1
Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1.7
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1.7	1.7
Fair Value, Inputs, Level 1 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,519.2
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,672.7	1,519.2
Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	127.9
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	131.6	127.9
Equity Securities [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	414.3
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	402.4	414.3
Equity Securities [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	40.1
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	38.7	40.1
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	180.1
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	165.5	180.1
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	18.2
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	16.7	18.2
Equity Securities - International [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	2,261.7
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	2,285.6	2,261.7
Equity Securities - International [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	144.7
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	146.3	144.7
Equity Securities - International [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities - International [Member] | Fair Value, Inputs, Level 2 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities - International [Member] | Fair Value, Inputs, Level 3 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities - International [Member] | Fair Value, Inputs, Level 3 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0.0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0.0	0.0
Equity Securities - International [Member] | Fair Value, Inputs, Level 1 [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	751.5
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	770.5	751.5
Equity Securities - International [Member] | Fair Value, Inputs, Level 1 [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	51.5
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	$ 52.0	$ 51.5