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			25.7					25.7
Stock-based compensation and additional related tax benefits			65.0	(5.2)			0.3	60.1
Treasury stock acquired, common						(245.2)		(245.2)
Dividends to common stockholders				(341.1)				(341.1)
Distributions to noncontrolling interest							(3.7)	(3.7)
Contributions from noncontrolling interest							0.7	0.7
Purchase of subsidiary shares from noncontrolling interest	[1]		15.1		(9.3)			5.8
Adjustments to redemption amount of redeemable noncontrolling interest			(4.1)					(4.1)
Net income (loss)	[1]			998.5			4.3	1,002.8
Other comprehensive income (loss)	[1]				983.6		1.8	985.4
Balances at Sep. 30, 2016		4.7	9,646.5	7,528.1	91.8	(6,476.5)	69.2	10,863.8
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			143.1					143.1
Stock-based compensation			68.1	(5.9)			0.2	62.4
Treasury stock acquired, common						(218.1)		(218.1)
Dividends to common stockholders				(398.5)				(398.5)
Distributions to noncontrolling interest							(6.1)	(6.1)
Contributions from noncontrolling interest							4.2	4.2
Purchase of subsidiary shares from noncontrolling interest	[1]		(7.6)				(1.3)	(8.9)
Adjustments to redemption amount of redeemable noncontrolling interest			(2.8)					(2.8)
Net income (loss)	[1]			1,468.6			6.1	1,474.7
Other comprehensive income (loss)	[1]				722.2		1.3	723.5
Balances at Sep. 30, 2017		$ 4.7	$ 9,886.8	$ 8,784.6	$ 47.0	$ (6,726.7)	$ 70.9	$ 12,067.3

[1] Excludes amounts attributable to redeemable noncontrolling interest. See Note 9, Stockholders’ Equity, for further details.