Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Accumulated other comprehensive loss	$ (3,858.6)	$ (2,670.1)
Other Comprehensive Income (Loss), Net of Tax	(1,188.5)	(198.2)	314.9
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	383.8
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	64.4
Other Comprehensive Income (Loss), Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	54.7	27.6	19.0
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	5.8	5.8	6.7
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive loss	(3,858.6)	(2,670.1)
Other Comprehensive Income (Loss), Net of Tax	(1,188.5)
Accumulated Translation Adjustment [Member]
Accumulated other comprehensive loss	265.9	510.7
Other Comprehensive Income (Loss), Net of Tax	(244.8)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive loss	14.8	128.9
Other Comprehensive Income (Loss), Net of Tax	(114.1)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated other comprehensive loss	(4,032.2)	(3,175.8)
Other Comprehensive Income (Loss), Net of Tax	(856.4)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated other comprehensive loss	(107.1)	(133.9)
Other Comprehensive Income (Loss), Net of Tax	$ 26.8