CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - USD ($) $ in Millions	Total	Common Stock Common Class A	Common Stock Common Class B	Common Stock Exchangeable Class A	Common Stock Exchangeable Class B	Paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Common stock held in treasury, Class B	Noncontrolling interest
Beginning balance at Dec. 31, 2018	$ 13,735.8	$ 0.0	$ 2.0	$ 103.2	$ 557.6	$ 6,773.1	$ 7,692.9	$ (1,150.0)	$ (471.4)	$ 228.4
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exchange of shares				(0.7)	0.2	0.5
Shares issued under equity compensation plan	(7.9)		0.1			(8.0)
Amortization of share-based compensation	7.3					7.3
Purchase of noncontrolling interest	0.6									0.6
Deconsolidation of VIE	(1.5)									(1.5)
Net income (loss) including noncontrolling interests	80.0						78.0			2.0
Other comprehensive income (loss), net of tax	(154.6)							(153.5)		(1.1)
Adoption of lease accounting standard	32.0						32.0
Reclassification of stranded tax effects							74.8	(74.8)
Contributions from noncontrolling interests	25.4									25.4
Distributions and dividends to noncontrolling interests	(9.7)									(9.7)
Dividends declared and paid	(300.9)						(300.9)
Ending balance at Sep. 30, 2019	13,406.5	0.0	2.1	102.5	557.8	6,772.9	7,576.8	(1,378.3)	(471.4)	244.1
Beginning balance at Jun. 30, 2019	14,145.0	0.0	2.1	103.0	557.9	6,783.3	8,103.1	(1,178.6)	(471.4)	245.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exchange of shares				(0.5)	(0.1)	0.6
Amortization of share-based compensation	(11.0)					(11.0)
Purchase of noncontrolling interest	(0.1)									(0.1)
Deconsolidation of VIE	(1.5)									(1.5)
Net income (loss) including noncontrolling interests	(399.3)						(402.8)			3.5
Other comprehensive income (loss), net of tax	(200.7)							(199.7)		(1.0)
Contributions from noncontrolling interests	3.9									3.9
Distributions and dividends to noncontrolling interests	(6.3)									(6.3)
Dividends declared and paid	(123.5)						(123.5)
Ending balance at Sep. 30, 2019	13,406.5	0.0	2.1	102.5	557.8	6,772.9	7,576.8	(1,378.3)	(471.4)	244.1
Beginning balance at Dec. 31, 2019	13,673.1	0.0	2.1	102.5	557.8	6,773.6	7,617.0	(1,162.2)	(471.4)	253.7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exchange of shares				(0.2)	(140.0)	140.2
Shares issued under equity compensation plan	(0.5)		0.0			(0.5)
Amortization of share-based compensation	18.0					18.0
Purchase of noncontrolling interest	(0.1)									(0.1)
Net income (loss) including noncontrolling interests	428.2						420.8			7.4
Other comprehensive income (loss), net of tax	(221.5)							(221.2)		(0.3)
Contributions from noncontrolling interests	14.0									14.0
Distributions and dividends to noncontrolling interests	(11.8)									(11.8)
Dividends declared and paid	(123.8)						(123.8)
Ending balance at Sep. 30, 2020	13,775.6	0.0	2.1	102.3	417.8	6,931.3	7,914.0	(1,383.4)	(471.4)	262.9
Beginning balance at Jun. 30, 2020	13,268.0	0.0	2.1	102.5	557.8	6,786.3	7,571.2	(1,545.6)	(471.4)	265.1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exchange of shares				(0.2)	(140.0)	140.2
Shares issued under equity compensation plan	(1.4)					(1.4)
Amortization of share-based compensation	6.2					6.2
Net income (loss) including noncontrolling interests	346.4						342.8			3.6
Other comprehensive income (loss), net of tax	163.7							162.2		1.5
Distributions and dividends to noncontrolling interests	(7.3)									(7.3)
Ending balance at Sep. 30, 2020	$ 13,775.6	$ 0.0	$ 2.1	$ 102.3	$ 417.8	$ 6,931.3	$ 7,914.0	$ (1,383.4)	$ (471.4)	$ 262.9