Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions		Common stock	Additional paid-in capital	Retained earnings (accumulated deficit)	Accumulated other comprehensive income (loss)	Treasury stock	Noncontrolling interest	Total
Balances at Dec. 31, 2015		$ 4.7	$ 9,544.8	$ 6,875.9	$ (882.5)	$ (6,231.3)	$ 65.8	$ 9,377.4
Increase (decrease) in stockholders' equity
Common stock issued			37.8					37.8
Stock-based compensation and additional related tax benefits			92.5	(7.1)			0.4	85.8
Treasury stock acquired, common						(277.3)		(277.3)
Dividends to common stockholders				(464.9)				(464.9)
Distributions to noncontrolling interest							(34.8)	(34.8)
Contributions from noncontrolling interest							5.5	5.5
Purchase of subsidiary shares from noncontrolling interest	[1]		15.1		(9.3)			5.8
Adjustments to redemption amount of redeemable noncontrolling interest			(4.2)					(4.2)
Net income (loss)	[1]			1,316.5			28.5	1,345.0
Other comprehensive income (loss)	[1]				216.6		1.1	217.7
Balances at Dec. 31, 2016		4.7	9,686.0	7,720.4	(675.2)	(6,508.6)	66.5	10,293.8
Increase (decrease) in stockholders' equity
Common stock issued			162.5					162.5
Stock-based compensation			90.2	(7.9)			0.4	82.7
Treasury stock acquired, common						(220.4)		(220.4)
Dividends to common stockholders				(540.0)				(540.0)
Distributions to noncontrolling interest							(8.4)	(8.4)
Contributions from noncontrolling interest							6.0	6.0
Purchase of subsidiary shares from noncontrolling interest	[1]		(7.6)				(1.3)	(8.9)
Adjustments to redemption amount of redeemable noncontrolling interest			(5.9)					(5.9)
Net income (loss)	[1]			2,310.4			7.1	2,317.5
Other comprehensive income (loss)	[1]				840.7		2.3	843.0
Balances at Dec. 31, 2017		4.7	9,925.2	9,482.9	165.5	(6,729.0)	72.6	12,921.9
Increase (decrease) in stockholders' equity
Common stock issued		0.1	63.9					64.0
Stock-based compensation			84.9	(7.7)			(0.4)	76.8
Treasury stock acquired, common						(671.6)		(671.6)
Dividends to common stockholders				(598.6)				(598.6)
Distributions to noncontrolling interest							(13.5)	(13.5)
Contributions from noncontrolling interest							3.3	3.3
Purchase of subsidiary shares from noncontrolling interest	[1]		(20.6)		(1.6)		(1.8)	(24.0)
Adjustments to redemption amount of redeemable noncontrolling interest			7.3				(0.3)	7.0
Effects of implementation of accounting change | ASU 2016-16 - Intra-entity asset transfer taxes				8.7				8.7
Effects of implementation of accounting change | ASU 2016-01 - Equity investments				1.0	(1.0)
Effects of implementation of accounting change | ASU 2014-09 - Revenue recognition				(65.0)	25.6		(0.3)	(39.7)
Effects of implementation of accounting change | ASU 2018-02 - Reclassification of certain tax effects				(77.6)	77.6
Net income (loss)	[1]			1,546.5			9.3	1,555.8
Other comprehensive income (loss)	[1]				(1,831.2)		(2.9)	(1,834.1)
Balances at Dec. 31, 2018		$ 4.8	$ 10,060.7	$ 10,290.2	$ (1,565.1)	$ (7,400.6)	$ 66.0	$ 11,456.0

[1] Excludes amounts attributable to redeemable noncontrolling interest. See Note 13, Stockholders’ Equity, for further details.