Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 26, 2019	Jun. 27, 2019	Mar. 28, 2019	Dec. 31, 2018	Sep. 27, 2018	Jun. 28, 2018	Mar. 29, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 24, 2018	Jul. 25, 2017	Nov. 01, 2016
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	$ (109.2)				$ (196.6)				$ (109.2)	$ (196.6)
Class of Stock [Line Items]
Employee Stock Purchase Plan, Number of Allocated Shares	1,000,000								1,000,000
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred Stock, Shares Authorized	10,000,000				10,000,000				10,000,000	10,000,000
Equity, Class of Treasury Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.12	$ 0.10	$ 0.48	$ 0.46	$ 0.40
Treasury Stock, Shares, Acquired									800,000	9,300,000	14,200,000
Issued But Unvested Shares (in shares)	1,400,000				1,400,000				1,400,000	1,400,000	1,500,000
Noncontrolling interest	$ 0.5				$ 0.5				$ 0.5	$ 0.5
Stock Repurchased During Period, Value	$ 649.6								75.8	800.0
Payments of Dividends									(50.4)	(48.0)	$ (47.1)
Basic EPS
(Loss) income available to common shareholders									$ 529.7	$ 616.5	$ 354.7
(Loss) income available to common shareholders (in shares)									103,600,000	108,000,000.0	116,800,000
Earnings Per Share, Basic	$ 0.65	$ 1.27	$ 1.62	$ 1.57	$ 1.70	$ 1.61	$ 1.32	$ 1.11	$ 5.11	$ 5.71	$ 3.04
Income allocated to participating securities									$ 0.4	$ 0.5	$ 0.2
Income allocated to participating securities, shares									100,000	100,000	100,000
Net income	$ 67.7	$ 131.3	$ 168.0	$ 163.1	$ 177.6	$ 168.8	$ 145.2	$ 125.4	$ 530.1	$ 617.0	$ 354.9
Diluted potential common shares (in shares)									1,000,000.0	1,000,000.0	1,000,000.0
Diluted EPS
Net income	$ 67.7	$ 131.3	$ 168.0	$ 163.1	$ 177.6	$ 168.8	$ 145.2	$ 125.4	$ 530.1	$ 617.0	$ 354.9
Shares									104,700,000	109,100,000	117,900,000
(Loss) earnings per share, diluted (in dollars per share)	$ 0.65	$ 1.26	$ 1.61	$ 1.55	$ 1.68	$ 1.59	$ 1.31	$ 1.10	$ 5.06	$ 5.65	$ 3.01
2015 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Value										$ 50.0
2016 Share Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 600.0								$ 600.0
Stock Repurchased During Period, Value										$ 600.0
2017 Share Repurchase Program [Member] [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount												$ 500.0	$ 400.0	$ 600.0
Common Class A [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common Stock, Shares Authorized	200,000,000				200,000,000				200,000,000	200,000,000
Class B [Member]
Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Common Stock, Shares Authorized	0				0				0	0