Stockholders' Equity - Repurchase Program (Details)				2 Months Ended	3 Months Ended			12 Months Ended	35 Months Ended	38 Months Ended
	Jan. 29, 2019 shares	Dec. 14, 2018 USD ($) $ / shares shares	Feb. 04, 2016 USD ($)	Jan. 29, 2019 $ / shares	Mar. 31, 2019 USD ($)		Mar. 31, 2018 USD ($)	Dec. 31, 2018 transaction	Dec. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) shares	Jan. 23, 2019 USD ($)
Class of Stock [Line Items]
Shares repurchased					$ 3,322,000		$ 88,292,000
Repurchase of common stock					3,322,000	[1]	$ 88,292,000
Shares repurchased (in shares) | shares	117,751	1,057,035
Initial price paid (in dollars per share) | $ / shares		$ 176.91
Final price paid (in dollars per share) | $ / shares				$ 187.27
Number of transactions | transaction								2
Common Stock
Class of Stock [Line Items]
Stock repurchase program, approved amount			$ 2,100,000,000.0
Stock repurchase program, authorized time period			18 months
Increase in authorized amount to be repurchased											$ 500,000,000
Remaining authorized repurchase amount					$ 545,000,000					$ 545,000,000
Repurchase agreements
Class of Stock [Line Items]
Shares repurchased									$ 1,600,000,000	$ 1,600,000,000
Repurchase of common stock		$ 220,000,000
Shares repurchased (in shares) | shares										9,052,163
Repurchase agreements | Common Stock
Class of Stock [Line Items]
Stock repurchase program, approved amount		$ 220,000,000

[1] Reflects the impact of the Company's adoption of Accounting Standards Update 2016-18, "Statement of Cash Flows (Topic 230)", which was adopted by the Company on January 1, 2018 and applied retrospectively to results for 2017. The adoption of Topic 230 resulted in the statement of cash flows presenting the changes in the total of cash, cash equivalents and restricted cash. As a result, the Company will no longer present transfers between cash and cash equivalents and restricted cash in the statement of cash flows.