Accumulated Other Comprehensive Income (Loss) (Components Of Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Postretirement Benefit Liability [Member]	Dec. 31, 2010 Postretirement Benefit Liability [Member]	Dec. 31, 2009 Postretirement Benefit Liability [Member]	Dec. 31, 2008 Postretirement Benefit Liability [Member]	Dec. 31, 2011 Foreign Currency Translation Adjustment [Member]	Dec. 31, 2010 Foreign Currency Translation Adjustment [Member]	Dec. 31, 2009 Foreign Currency Translation Adjustment [Member]	Dec. 31, 2008 Foreign Currency Translation Adjustment [Member]	Dec. 31, 2011 Unrealized Gain (Loss) On Derivatives [Member]	Dec. 31, 2010 Unrealized Gain (Loss) On Derivatives [Member]	Dec. 31, 2009 Unrealized Gain (Loss) On Derivatives [Member]	Dec. 31, 2008 Unrealized Gain (Loss) On Derivatives [Member]	Dec. 31, 2011 Accumulated Net Unrealized Investment Gain (Loss) On Securities [Member]	Dec. 31, 2010 Accumulated Net Unrealized Investment Gain (Loss) On Securities [Member]	Dec. 31, 2009 Accumulated Net Unrealized Investment Gain (Loss) On Securities [Member]	Dec. 31, 2008 Accumulated Net Unrealized Investment Gain (Loss) On Securities [Member]
Pre-tax Amount	$ (299.2)	$ (71.3)	$ (240.0)	$ (615.9)	$ (452.0)	$ (451.9)		$ 312.5	$ 329.9	$ 163.1		$ 1.7	$ 3.9	$ 5.7		$ 2.5	$ 46.9	$ 43.1
Tax Benefit (Provision)	206.6	117.2	117.4	207.0	146.9	132.8			(15.2)			(0.5)	(1.2)	(1.7)		0.1	(13.3)	(13.7)
After-tax Amount	(92.6)	45.9	(122.6)	(408.9)	(305.1)	(319.1)	(343.3)	312.5	314.7	163.1	(68.6)	1.2	2.7	4.0	19.1	2.6	33.6	29.4	(0.1)
Unrealized net gain on derivative financial instruments, After-tax	$ (1.5)	$ (1.3)	$ (15.1)