Retirement Benefits (Schedule of Components in Consolidated Balance Sheets) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent		$ 2,160.3	$ 2,562.9
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Recognized in Net Periodic Benefit Cost, before Tax	[1]	(80.7)	(34.0)	$ (31.9)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Amortization of Net Gains (Losses)		(285.9)
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent		261.6	211.2
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities		(63.8)	(62.3)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent		1,921.4	2,325.6
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax		4,585.2	5,158.4
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total		2,861.6	2,981.7
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Gain (Loss), before Tax		(383.2)
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Recognized in Net Periodic Benefit Cost, before Tax		(10.4)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Change in Retiree Health Plan - Impact on Unrecognized Prior Service Cost		520.8
Defined Benefit Plan, Amortization of Net Gains (Losses)		(19.2)
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent		722.1	609.4
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities		(6.9)	(6.9)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent		238.9	237.3
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax		(226.9)	(227.2)
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total		249.4	$ 138.0
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss), Net Gain (Loss), before Tax		(38.0)
Other Comprehensive Income (Loss), Amortization, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost (Credit) Recognized in Net Periodic Benefit Cost, before Tax		$ 91.1

[1] (1) These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 14).