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Earnings Per Share - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands	1 Months Ended	3 Months Ended						5 Months Ended	9 Months Ended		28 Months Ended
	Apr. 05, 2019	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Aug. 31, 2017	Apr. 05, 2019	Feb. 28, 2019	Feb. 28, 2018	Nov. 30, 2018	Oct. 30, 2018	Aug. 02, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Basic earnings from discontinued operations (in dollars per share)		$ 0.02			$ 0.06				$ 0.02	$ 0.57
Diluted earnings from discontinued operations (in dollars per share)		$ 0.02			$ 0.05				$ 0.02	$ 0.55
Options granted and excluded from the computation of diluted earnings per share (in shares)		700			1,000				500	800
Stock purchased under share buyback		$ 100,095,000	$ 368,661,000	$ 139,468,000	$ 1,353,000	$ 657,000	$ 35,040,000
Employee Payroll Taxes Due on Restricted Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock purchased under share buyback (shares)		100							300
Stock purchased under share buyback, average price per share (in dollars per share)		$ 195.14							$ 204.31
Stock purchased under share buyback		$ 100,000							$ 61,600,000
August 2, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share buyback program, authorized amount													$ 500,000,000.0
Stock purchased under share buyback (shares)		0							2,130		2,600
Stock purchased under share buyback, average price per share (in dollars per share)		$ 0.00							$ 192.55		$ 188.82
Stock purchased under share buyback		$ 0							$ 410,003,000		$ 500,000,000
October 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share buyback program, authorized amount												$ 1,000,000,000.0
Stock purchased under share buyback (shares)		598							799
Stock purchased under share buyback, average price per share (in dollars per share)		$ 167.32							$ 170.87
Stock purchased under share buyback		$ 100,000,000							$ 136,579,000
Subsequent Event \| October 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock purchased under share buyback (shares)	400							1,200
Stock purchased under share buyback, average price per share (in dollars per share)	$ 203.26							$ 181.85
Stock purchased under share buyback	$ 83,300,000							$ 219,900,000