Condensed 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, 2020		$ 4.8	$ 10,321.6	$ 11,838.0	$ 2,383.1	$ (7,988.6)	$ 58.4	$ 16,617.3
Increase (decrease) in stockholders' equity
Common stock issued			57.3					57.3
Stock-based compensation			82.2	(7.3)			0.1	75.0
Treasury stock acquired, common						(585.1)		(585.1)
Dividends to common stockholders				(485.6)				(485.6)
Distributions to noncontrolling interest							(4.8)	(4.8)
Contributions from noncontrolling interest							5.4	5.4
Purchase of subsidiary shares from noncontrolling interest	[1]		(16.4)				(1.7)	(18.1)
Adjustments to redemption amount of redeemable noncontrolling interest			(8.2)				(0.4)	(8.6)
Net income (loss)	[1]			1,238.8			3.9	1,242.7
Other comprehensive income (loss)	[1]				(763.9)		(2.4)	(766.3)
Balances at Sep. 30, 2021		4.8	10,436.5	12,583.9	1,619.2	(8,573.7)	58.5	16,129.2
Balances at Jun. 30, 2021		4.8	10,399.7	12,395.0	1,803.8	(8,370.2)	58.4	16,291.5
Increase (decrease) in stockholders' equity
Common stock issued			14.4					14.4
Stock-based compensation			23.5	(2.8)			0.1	20.8
Treasury stock acquired, common						(203.5)		(203.5)
Dividends to common stockholders				(168.2)				(168.2)
Distributions to noncontrolling interest							(1.4)	(1.4)
Contributions from noncontrolling interest							1.6	1.6
Purchase of subsidiary shares from noncontrolling interest	[1]		(1.1)					(1.1)
Net income (loss)	[1]			359.9			1.7	361.6
Other comprehensive income (loss)	[1]				(184.6)		(1.9)	(186.5)
Balances at Sep. 30, 2021		4.8	10,436.5	12,583.9	1,619.2	(8,573.7)	58.5	16,129.2
Balances at Dec. 31, 2021		4.8	10,495.0	12,884.5	1,610.9	(8,925.8)	56.4	16,125.8
Increase (decrease) in stockholders' equity
Common stock issued		0.1	101.9					102.0
Stock-based compensation			79.6	(8.6)			0.2	71.2
Treasury stock acquired, common						(1,410.7)		(1,410.7)
Accelerated share repurchase			(33.9)					(33.9)
Dividends to common stockholders				(486.1)				(486.1)
Distributions to noncontrolling interest							(68.4)	(68.4)
Contributions from noncontrolling interest							5.2	5.2
Purchase of subsidiary shares from noncontrolling interest	[1]		(5.7)				(2.4)	(8.1)
Adjustments to redemption amount of redeemable noncontrolling interest			0.6				(0.5)	0.1
Adjustment for reinsurance					131.8			131.8
Net income (loss)	[1]			4,821.1			53.6	4,874.7
Other comprehensive income (loss)	[1]				(9,813.3)		(2.0)	(9,815.3)
Balances at Sep. 30, 2022		4.9	10,637.5	17,210.9	(8,070.6)	(10,336.5)	42.1	9,488.3
Balances at Jun. 30, 2022		4.9	10,553.5	15,985.6	(5,630.1)	(9,877.1)	41.8	11,078.6
Increase (decrease) in stockholders' equity
Common stock issued			53.0					53.0
Stock-based compensation			23.1	(2.8)				20.3
Treasury stock acquired, common						(459.4)		(459.4)
Accelerated share repurchase			8.9					8.9
Dividends to common stockholders				(157.4)				(157.4)
Distributions to noncontrolling interest							(1.4)	(1.4)
Contributions from noncontrolling interest							1.5	1.5
Purchase of subsidiary shares from noncontrolling interest	[1]		(1.4)					(1.4)
Adjustments to redemption amount of redeemable noncontrolling interest			0.4				0.1	0.5
Net income (loss)	[1]			1,385.5			0.5	1,386.0
Other comprehensive income (loss)	[1]				(2,440.5)		(0.4)	(2,440.9)
Balances at Sep. 30, 2022		$ 4.9	$ 10,637.5	$ 17,210.9	$ (8,070.6)	$ (10,336.5)	$ 42.1	$ 9,488.3

[1] Excludes amounts attributable to redeemable noncontrolling interest. See Note 11, Stockholders’ Equity, for further details.