Retirement Benefits (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension and Other Postretirement Benefit Contributions			$ 80
Pension and Other Postretirement Benefit Contributions, Discretionary			250
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Service Cost	57.7	54.7	174.7	165.5
Defined Benefit Plan, Interest Cost	111.8	107.9	335.8	323.7
Defined Benefit Plan, Actuarial Net (Gains) Losses	50.4	41.2	149.2	123.5
Defined Benefit Plan, Expected Return on Plan Assets	(171.9)	(158.8)	(515.2)	(476.4)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	2.2	1.7	6.9	5.0
Defined Benefit Plan, Net Periodic Benefit Cost, Total	50.2	46.7	151.4	141.3
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Service Cost	14.4	14.1	43.1	42.2
Defined Benefit Plan, Interest Cost	29.5	30.3	88.6	90.2
Defined Benefit Plan, Actuarial Net (Gains) Losses	22.2	21.3	66.5	63.8
Defined Benefit Plan, Expected Return on Plan Assets	(31.9)	(30.6)	(95.7)	(92.0)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(10.7)	(9.3)	(32.2)	(27.9)
Defined Benefit Plan, Net Periodic Benefit Cost, Total	$ 23.5	$ 25.8	$ 70.3	$ 76.3