Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Contributions			$ 35.0
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year			15.0
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Service Cost	$ 70.2	$ 82.8	212.2	$ 245.3
Defined Benefit Plan, Interest Cost	104.2	117.1	314.4	351.4
Defined Benefit Plan, Expected Return on Plan Assets	(187.6)	(195.7)	(566.7)	(579.7)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	2.9	2.5	8.6	7.6
Defined Benefit Plan, Actuarial Gain (Loss)	71.0	91.5	213.4	274.8
Defined Benefit Plan, Net Periodic Benefit Cost, Total	60.7	98.2	181.9	299.4
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Service Cost	9.7	10.5	29.3	31.5
Defined Benefit Plan, Interest Cost	13.0	15.3	39.0	46.0
Defined Benefit Plan, Expected Return on Plan Assets	(37.6)	(37.1)	(112.7)	(111.3)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(21.5)	(21.6)	(64.3)	(64.8)
Defined Benefit Plan, Actuarial Gain (Loss)	5.2	9.4	15.5	28.3
Defined Benefit Plan, Net Periodic Benefit Cost, Total	$ (31.2)	$ (23.5)	$ (93.2)	$ (70.3)