Stockholders' Equity - Repurchase Program (Details)			2 Months Ended	3 Months Ended		6 Months Ended	50 Months Ended
	Jan. 29, 2019 shares	Dec. 14, 2018 USD ($) $ / shares shares	Jan. 29, 2019 $ / shares	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Jun. 30, 2019 transaction	Mar. 31, 2020 USD ($) shares	Oct. 22, 2019 USD ($)
Class of Stock [Line Items]
Shares repurchased				$ 530,237,000	$ 3,322,000
Repurchase of common stock				530,237,000	$ 3,322,000
Number of transactions | transaction						2
Program
Class of Stock [Line Items]
Shares repurchased (in shares) | shares							13,308,964
Shares repurchased							$ 2,800,000,000
Program | Common Stock
Class of Stock [Line Items]
Increase in authorized amount to be repurchased								$ 1,000,000,000
Stock repurchase program, approved amount								$ 3,100,000,000
Remaining authorized repurchase amount				$ 326,300,000			$ 326,300,000
2019 ASR Agreement
Class of Stock [Line Items]
Shares repurchased (in shares) | shares	175,340	1,431,989
Repurchase of common stock		$ 500,000,000
Initial price paid (in dollars per share) | $ / shares		$ 285.70
Final price paid (in dollars per share) | $ / shares			$ 306.81
2019 ASR Agreement | Common Stock
Class of Stock [Line Items]
Stock repurchase program, approved amount		$ 500,000,000