Other Comprehensive Income (Loss) (Schedule of Component of Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2018	Jan. 01, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 10,909.1
Reclassification of stranded tax effects and Adoption of new accounting standards				$ (128.9)
Other comprehensive income (loss) before reclassifications	(997.6)	$ (106.9)	$ 114.0
Net amount reclassified from accumulated other comprehensive loss	214.2	190.5	60.5
Net other comprehensive income (loss)	(783.4)	83.6	174.5
Reclassifications of stranded tax effects (Note 1)			(643.6)
Ending balance	2,699.1	10,909.1
Accumulated other comprehensive income (loss)	(6,523.6)	(5,729.2)
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(5,740.2)	(5,694.9)	(5,225.8)
Ending balance	(6,523.6)	(5,740.2)	(5,694.9)
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(5,729.2)	(5,718.6)	(5,274.0)
Reclassification of stranded tax effects and Adoption of new accounting standards				(105.2)
Reclassifications of stranded tax effects (Note 1)			(643.6)
Ending balance	(6,523.6)	(5,729.2)	(5,718.6)
Accumulated other comprehensive income (loss)		(5,730.0)	(5,720.0)		$ (5,270.0)
AOCI Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification of stranded tax effects and Adoption of new accounting standards				(23.7)
Accumulated other comprehensive income (loss)		11.0	23.7		$ 48.2
Continuing Operations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net other comprehensive income (loss)	(840.2)	69.3	45.3
Continuing Operations | Foreign Currency Translation Gains (Losses)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,569.7)	(1,191.7)	(1,686.6)
Reclassification of stranded tax effects and Adoption of new accounting standards				0.0
Other comprehensive income (loss) before reclassifications	(46.2)	(378.0)	525.6
Net amount reclassified from accumulated other comprehensive loss	(62.1)	0.0	8.1
Net other comprehensive income (loss)	(108.3)	(378.0)	533.7
Reclassifications of stranded tax effects (Note 1)			(38.8)
Ending balance	(1,678.0)	(1,569.7)	(1,191.7)
Continuing Operations | Unrealized Net Gains (Losses) on Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(22.1)	113.5	224.0
Reclassification of stranded tax effects and Adoption of new accounting standards				(128.9)
Other comprehensive income (loss) before reclassifications	28.9	24.5	(15.7)
Net amount reclassified from accumulated other comprehensive loss	(1.9)	(31.2)	(110.6)
Net other comprehensive income (loss)	27.0	(6.7)	(126.3)
Reclassifications of stranded tax effects (Note 1)			15.8
Ending balance	4.9	(22.1)	113.5
Continuing Operations | Defined Benefit Pension and Retiree Health Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(3,852.7)	(4,311.3)	(3,352.0)
Reclassification of stranded tax effects and Adoption of new accounting standards				0.0
Other comprehensive income (loss) before reclassifications	(967.6)	250.7	(532.1)
Net amount reclassified from accumulated other comprehensive loss	181.7	207.9	151.9
Net other comprehensive income (loss)	(785.9)	458.6	(380.2)
Reclassifications of stranded tax effects (Note 1)			(579.1)
Ending balance	(4,638.6)	(3,852.7)	(4,311.3)
Continuing Operations | Effective Portion of Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(234.3)	(210.9)
Reclassification of stranded tax effects and Adoption of new accounting standards				0.0
Other comprehensive income (loss) before reclassifications		(16.3)	8.5
Net amount reclassified from accumulated other comprehensive loss		11.7	9.6
Net other comprehensive income (loss)		(4.6)	18.1
Reclassifications of stranded tax effects (Note 1)			(41.5)
Ending balance			(234.3)
Continuing Operations | Effective Portion of Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(238.9)
Other comprehensive income (loss) before reclassifications	14.5
Net amount reclassified from accumulated other comprehensive loss	12.5
Net other comprehensive income (loss)	27.0
Ending balance	(211.9)	(238.9)
Discontinued Operations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net other comprehensive income (loss)	56.8	14.3	129.2
Discontinued Operations | Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(56.8)	(71.1)	(200.3)
Reclassification of stranded tax effects and Adoption of new accounting standards				$ 0.0
Other comprehensive income (loss) before reclassifications	(27.2)	12.2	127.7
Net amount reclassified from accumulated other comprehensive loss	84.0	2.1	1.5
Net other comprehensive income (loss)	56.8	14.3	129.2
Reclassifications of stranded tax effects (Note 1)			0.0
Ending balance	$ 0.0	$ (56.8)	$ (71.1)