Equity Items - Additional Information (Details) - USD ($) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended							9 Months Ended
	May 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2019
Accelerated Share Repurchases [Line Items]
Payments for repurchase of common stock									$ 200,000,000
Common Stock, Dividends, Per Share, Paid		$ 0.275	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.225	$ 0.225
Percentage of increase in cash dividend		10.00%				11.00%
2018 Stock Repurchase Program [Member]
Accelerated Share Repurchases [Line Items]
Stock Repurchase Program, Authorized Amount							$ 1,000,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 800,000,000							$ 800,000,000
2019 Accelerated Share Repurchase Agreement [Member]
Accelerated Share Repurchases [Line Items]
Payments for repurchase of common stock	$ 200,000,000
Common stock repurchased	2.2