Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Year	$ 37.3	$ (814.2)
Other Comprehensive Income (Loss) Before Reclassifications	(286.0)	317.2
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(31.6)	5.3
Total Other Comprehensive Income (Loss)	(254.4)	311.9
Balance at End of Period	(217.1)	(502.3)
Net Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Year	615.9	(312.4)
Other Comprehensive Income (Loss) Before Reclassifications	(263.2)	305.4
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(42.6)	(6.9)
Total Other Comprehensive Income (Loss)	(220.6)	312.3
Balance at End of Period	395.3	(0.1)
Net Gain on Hedges
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Year	187.8	250.6
Other Comprehensive Income (Loss) Before Reclassifications	37.7	(4.7)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	14.9	15.8
Total Other Comprehensive Income (Loss)	22.8	(20.5)
Balance at End of Period	210.6	230.1
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Year	(281.6)	(305.2)
Other Comprehensive Income (Loss) Before Reclassifications	(63.6)	17.3
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	0.0	0.0
Total Other Comprehensive Income (Loss)	(63.6)	17.3
Balance at End of Period	(345.2)	(287.9)
Unrecognized Pension and Postretirement Benefit Costs
Accumulated Other Comprehensive Income (Loss)
Balance at Beginning of Year	(484.8)	(447.2)
Other Comprehensive Income (Loss) Before Reclassifications	3.1	(0.8)
Amounts Reclassified from Accumulated Other Comprehensive Income or Loss	(3.9)	(3.6)
Total Other Comprehensive Income (Loss)	7.0	2.8
Balance at End of Period	$ (477.8)	$ (444.4)