Other Comprehensive Income (Loss) Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax				$ 74.5
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax		$ 14.4	$ (5.9)	16.1	$ (17.7)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Prior Service Cost Arising During Period, before Tax	[1]	(18.6)	(19.1)	(55.7)	(57.2)
Accumulated other comprehensive loss		(4,257.7)	(4,667.0)	(4,257.7)	(4,667.0)	$ (4,371.2)	$ (4,580.7)	$ (4,403.2)	$ (3,991.8)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		73.4	(226.7)	117.4	(713.1)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax		40.1	(37.1)	205.6	37.9
Other comprehensive income (loss), net of tax		113.5	(263.8)	323.0	(675.2)
Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, before Tax	[1]	76.2	100.9	228.9	303.1
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax		57.6	81.8	173.2	245.9
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Tax		(19.6)	(27.0)	(62.7)	(83.0)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net (Gain) Loss, Net of Tax		38.0	54.8	110.5	162.9
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		(12.0)	(149.5)	(6.8)	(213.9)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax		11.4	4.5	27.3	10.7
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax		(0.6)	(145.0)	20.5	(203.2)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax		0.2	50.7	(7.2)	71.1
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		(0.4)	(94.3)	13.3	(132.1)
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax		(26.1)	(59.6)	(40.5)	(48.2)
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, before Reclassification Adjustments, Tax		(9.5)	31.1	(57.0)	93.9
Other Comprehensive Income, Other, Net of Tax	[2]	2.5	2.4	81.8	7.1
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax		(1.3)	1.3	(2.7)	(15.9)
Other Comprehensive Income (Loss), Tax		(22.5)	(33.1)	(84.1)	12.1
Accumulated Translation Adjustment [Member]
Accumulated other comprehensive loss		(1,267.2)	(1,264.3)	(1,267.2)	(1,264.3)	(1,273.0)	(1,360.2)	(1,037.6)	(498.4)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		5.8	(226.7)	18.5	(765.9)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax		0.0	0.0	74.5	0.0
Other comprehensive income (loss), net of tax		5.8	(226.7)	93.0	(765.9)
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated other comprehensive loss		85.3	10.5	85.3	10.5	36.8	10.1	121.0	99.7
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		48.9	(16.2)	61.9	42.9
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax		(0.4)	(94.3)	13.3	(132.1)
Other comprehensive income (loss), net of tax		48.5	(110.5)	75.2	(89.2)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated other comprehensive loss		(2,862.4)	(3,192.3)	(2,862.4)	(3,192.3)	(2,919.1)	(3,012.1)	(3,263.3)	(3,402.0)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		18.7	16.2	39.2	46.8
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax		38.0	54.8	110.5	162.9
Other comprehensive income (loss), net of tax		56.7	71.0	149.7	209.7
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated other comprehensive loss		(213.4)	(220.9)	(213.4)	(220.9)	$ (215.9)	$ (218.5)	$ (223.3)	$ (191.1)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax		0.0	0.0	(2.2)	(36.9)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, Net of Tax		2.5	2.4	7.3	7.1
Other comprehensive income (loss), net of tax		$ 2.5	$ 2.4	$ 5.1	$ (29.8)

[1] (1) These accumulated other comprehensive loss components are included in the computation of net periodic benefit (income) cost (see Note 9).

[2] (2) Amount for the nine months ended September 30, 2016 included primarily $74.5 million of foreign currency translation losses.