Earnings Per Share - Treasury Stock Narrative (Details) - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 08, 2016	Feb. 29, 2016	Feb. 29, 2016	Sep. 30, 2015	Aug. 04, 2015	Jan. 13, 2015
Equity, Class of Treasury Stock [Line Items]
Shares		1,188,000	5,662,000	5,900,000
Average price per share (in dollars per share)		$ 84.15	$ 85.29	$ 84.07
Purchase price		$ 99,997,000	$ 482,915,000	$ 500,000,000
Employee payroll taxes due on restricted stock
Equity, Class of Treasury Stock [Line Items]
Shares			200,000
Average price per share (in dollars per share)			$ 85.62
Purchase price		$ 100,000	$ 19,500,000
January 13, 2015
Equity, Class of Treasury Stock [Line Items]
Share buyback program, authorized amount						$ 500,000,000.0
Shares		0	3,078,000
Average price per share (in dollars per share)		$ 0.00	$ 85.44
Purchase price		$ 0	$ 262,937,000
August 4, 2015
Equity, Class of Treasury Stock [Line Items]
Share buyback program, authorized amount					$ 500,000,000.0
Shares		1,188,000	2,584,000
Average price per share (in dollars per share)		$ 84.15	$ 85.11
Purchase price		$ 99,997,000	$ 219,978,000
Subsequent Event
Equity, Class of Treasury Stock [Line Items]
Shares	500,000
Purchase price	$ 47,800,000
Subsequent Event | Employee payroll taxes due on restricted stock
Equity, Class of Treasury Stock [Line Items]
Shares	0