Retirement Benefits (Schedule of Benefit Obligations and Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	$ 8,115.0	$ 7,553.9
Defined Benefit Plan, Service Cost	236.3	219.2	242.1
Defined Benefit Plan, Interest Cost	447.9	431.6	417.5
Defined Benefit Plan, Actuarial Net (Gains) Losses	794.7	342.2
Defined Benefit Plan, Benefits Paid	(400.1)	(387.8)
Defined Benefit Plan, Plan Amendments	10.0	0.3
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(12.6)	(44.4)
Defined Benefit Plan, Benefit Obligation, Ending Balance	9,191.2	8,115.0	7,553.9
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	6,983.0	6,008.5
Defined Benefit Plan, Actual Return on Plan Assets	209.2	818.3
Defined Benefit Plan, Contributions by Employer	402.4	563.5
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	(8.2)	(19.5)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	7,186.3	6,983.0	6,008.5
Defined Benefit Plan, Funded Status of Plan	(2,004.9)	(1,132.0)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(4,857.5)	(3,796.6)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	57.3	56.1
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total	2,909.9	2,720.7
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Benefit Obligation, Beginning Balance	2,088.5	2,032.8
Defined Benefit Plan, Service Cost	72.4	56.5	53.7
Defined Benefit Plan, Interest Cost	118.0	121.4	119.6
Defined Benefit Plan, Actuarial Net (Gains) Losses	110.2	10.0
Defined Benefit Plan, Benefits Paid	(77.9)	(98.0)
Defined Benefit Plan, Plan Amendments	1.1	(64.2)
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Benefit Obligation	(3.7)	30.0
Defined Benefit Plan, Benefit Obligation, Ending Balance	2,308.6	2,088.5	2,032.8
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	1,327.7	1,180.7
Defined Benefit Plan, Actual Return on Plan Assets	16.6	152.2
Defined Benefit Plan, Contributions by Employer	72.6	92.8
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	0	0
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	1,339.0	1,327.7	1,180.7
Defined Benefit Plan, Funded Status of Plan	(969.6)	(760.8)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(1,367.4)	(1,235.3)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	(215.1)	(261.1)
Defined Benefit Plan, Amounts Recognized in Balance Sheet, Total	$ 182.7	$ 213.4