Schedule of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated Other Comprehensive Income, Net of Tax
Balance at Beginning of Period	$ (51.0)	$ 16.1
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	58.5	182.0
Reclassification from Accumulated Other Comprehensive Income or Loss	(7.1)	2.6
Net Other Comprehensive Income (Loss)	51.4	184.6
Balance at End of Period	0.4	200.7
Net Unrealized Gain on Securities
Accumulated Other Comprehensive Income, Net of Tax
Balance at Beginning of Period	440.6	204.3
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	44.7	223.8
Reclassification from Accumulated Other Comprehensive Income or Loss	(2.3)	10.3
Net Other Comprehensive Income (Loss)	42.4	234.1
Balance at End of Period	483.0	438.4
Net Gain on Cash Flow Hedges
Accumulated Other Comprehensive Income, Net of Tax
Balance at Beginning of Period	327.5	378.0
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	(2.7)	(15.9)
Reclassification from Accumulated Other Comprehensive Income or Loss	(8.0)	(10.3)
Net Other Comprehensive Income (Loss)	(10.7)	(26.2)
Balance at End of Period	316.8	351.8
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income, Net of Tax
Balance at Beginning of Period	(354.0)	(173.6)
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	17.1	(26.4)
Reclassification from Accumulated Other Comprehensive Income or Loss	0.0	0.0
Net Other Comprehensive Income (Loss)	17.1	(26.4)
Balance at End of Period	(336.9)	(200.0)
Unrecognized Pension and Postretirement Benefit Costs
Accumulated Other Comprehensive Income, Net of Tax
Balance at Beginning of Period	(465.1)	(392.6)
Other Comprehensive Income (Loss) Before Reclassifications, Net of Tax	(0.6)	0.5
Reclassification from Accumulated Other Comprehensive Income or Loss	3.2	2.6
Net Other Comprehensive Income (Loss)	2.6	3.1
Balance at End of Period	$ (462.5)	$ (389.5)