Schedule of Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income, Net of Tax
Balance, Beginning of Period	$ 166.4	$ 255.0
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	92.7	203.1
Reclassification from Accumulated Other Comprehensive Income or Loss	1.3	(3.7)
Net Other Comprehensive Income (Loss)	94.0	199.4
Balance, End of Period	260.4	454.4
Net Unrealized Gain on Securities
Accumulated Other Comprehensive Income, Net of Tax
Balance, Beginning of Period	290.3	135.7
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	118.0	187.2
Reclassification from Accumulated Other Comprehensive Income or Loss	6.0	2.4
Net Other Comprehensive Income (Loss)	124.0	189.6
Balance, End of Period	414.3	325.3
Net Gain on Cash Flow Hedges
Accumulated Other Comprehensive Income, Net of Tax
Balance, Beginning of Period	391.0	396.3
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	27.6	8.5
Reclassification from Accumulated Other Comprehensive Income or Loss	(6.7)	(6.8)
Net Other Comprehensive Income (Loss)	20.9	1.7
Balance, End of Period	411.9	398.0
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income, Net of Tax
Balance, Beginning of Period	(113.4)	(47.1)
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	(54.0)	7.6
Reclassification from Accumulated Other Comprehensive Income or Loss	0	0
Net Other Comprehensive Income (Loss)	(54.0)	7.6
Balance, End of Period	(167.4)	(39.5)
Unrecognized Pension and Postretirement Benefit Costs
Accumulated Other Comprehensive Income, Net of Tax
Balance, Beginning of Period	(401.5)	(229.9)
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	1.1	(0.2)
Reclassification from Accumulated Other Comprehensive Income or Loss	2.0	0.7
Net Other Comprehensive Income (Loss)	3.1	0.5
Balance, End of Period	$ (398.4)	$ (229.4)