Other Comprehensive Income (Loss) (AOCI) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016		Jun. 30, 2017		Dec. 31, 2016		Jun. 30, 2016	[3]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				$ 14,080.5				$ 14,169.7		$ 14,080.5
Other comprehensive income (loss) before reclassifications		$ 257.5	$ (156.4)	447.4		$ 44.0
Net amount reclassified from accumulated other comprehensive loss		27.3	49.9	36.1		165.5
Net other comprehensive income (loss)	[1]	284.8	(106.5)	483.5		209.5
Ending balance				14,080.5
Accumulated other comprehensive loss								4,774.9		5,274.0
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(1,648.7)	(1,085.4)	(1,867.3)	[2]	(1,360.2)	[2]	(1,349.4)	[3]	(1,867.3)	[2]	$ (1,273.0)
Other comprehensive income (loss) before reclassifications		299.3	(187.6)	517.9		12.7
Net amount reclassified from accumulated other comprehensive loss		0.0	0.0	0.0		74.5
Net other comprehensive income (loss)		299.3	(187.6)	517.9		87.2
Ending balance		(1,648.7)	(1,085.4)	(1,867.3)	[2]	(1,360.2)	[2]
Accumulated Other Comprehensive Loss
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(5,027.1)	(4,264.7)	(5,225.8)	[2]	(4,580.7)	[2]	(4,742.3)	[3]	(5,225.8)	[2]	(4,371.2)
Ending balance		(5,027.1)	(4,264.7)	(5,225.8)	[2]	(4,580.7)	[2]
Unrealized gains/losses on available-for-sale securities:
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		179.4	17.9	224.0	[2]	10.1	[2]	153.2	[3]	224.0	[2]	36.8
Other comprehensive income (loss) before reclassifications		(12.5)	8.8	(24.3)		13.0
Net amount reclassified from accumulated other comprehensive loss		(13.7)	10.1	(46.5)		13.7
Net other comprehensive income (loss)		(26.2)	18.9	(70.8)		26.7
Ending balance		179.4	17.9	224.0	[2]	10.1	[2]
AOCI Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss								4,774.9		5,274.0
AOCI Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Accumulated other comprehensive loss								(32.6)		(48.2)
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(3,349.4)	(2,981.1)	(3,371.6)	[2]	(3,012.1)	[2]	(3,348.5)	[3]	(3,371.6)	[2]	(2,919.1)
Other comprehensive income (loss) before reclassifications		(37.7)	24.6	(54.6)		20.5
Net amount reclassified from accumulated other comprehensive loss		38.6	37.4	77.7		72.5
Net other comprehensive income (loss)		0.9	62.0	23.1		93.0
Ending balance		(3,349.4)	(2,981.1)	(3,371.6)	[2]	(3,012.1)	[2]
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(208.4)	(216.1)	(210.9)	[2]	(218.5)	[2]	$ (197.6)	[3]	$ (210.9)	[2]	$ (215.9)
Other comprehensive income (loss) before reclassifications		8.4	(2.2)	8.4		(2.2)
Net amount reclassified from accumulated other comprehensive loss		2.4	2.4	4.9		4.8
Net other comprehensive income (loss)		10.8	0.2	13.3		2.6
Ending balance		$ (208.4)	$ (216.1)	$ (210.9)	[2]	$ (218.5)	[2]

[1] (1) Other comprehensive income (loss) for the three and six months ended June 30, 2017 consisted of $289.4 million and $499.1 million of other comprehensive income attributable to controlling interest, respectively, and $(4.6) million and $(15.6) million of other comprehensive income (loss) attributable to non-controlling interest, respectively. Other comprehensive income (loss) for the three and six months ended June 30, 2016 attributable to non-controlling interest is immaterial.

[2] (1) Accumulated other comprehensive loss as of January 1, 2017 consists of $5,274.0 million of accumulated other comprehensive loss attributable to controlling interest and $48.2 million of accumulated other comprehensive income attributable to non-controlling interest. The accumulated other comprehensive loss attributable to non-controlling interest as of January 1, 2016 is immaterial.

[3] (2) Accumulated other comprehensive loss as of June 30, 2017 consists of $4,774.9 million of accumulated other comprehensive loss attributable to controlling interest and $32.6 million of accumulated other comprehensive income attributable to non-controlling interest. The accumulated other comprehensive loss attributable to non-controlling interest as of June 30, 2016 is immaterial.