Condensed Consolidating Financial Statements - Narrative (Details) - USD ($)	Sep. 30, 2020	Aug. 17, 2020	Dec. 31, 2019	Nov. 26, 2019	May 17, 2018	Sep. 22, 2016	Aug. 18, 2015	May 26, 2015
Condensed Financial Statements, Captions [Line Items]
Ownership interest of subsidiary (as a percent)	100.00%
Senior Notes
Condensed Financial Statements, Captions [Line Items]
Debt issued							$ 2,000,000,000.0
Senior Notes | 2.5% Senior Notes due 2029
Condensed Financial Statements, Captions [Line Items]
Debt issued				$ 500,000,000
Stated interest rate (as a percent)	2.50%			2.50%
Senior Notes | 3.25% Senior Notes due 2049
Condensed Financial Statements, Captions [Line Items]
Debt issued				$ 600,000,000
Stated interest rate (as a percent)	3.25%			3.25%
Senior Notes | 3.3% Senior Notes due 2020
Condensed Financial Statements, Captions [Line Items]
Debt issued							$ 700,000,000
Stated interest rate (as a percent)							3.30%
Senior Notes | 6.55% Senior Notes due 2037
Condensed Financial Statements, Captions [Line Items]
Debt issued			$ 400,000,000
Stated interest rate (as a percent)	6.55%		6.55%
Senior Notes | 4.5% Senior Notes due 2048
Condensed Financial Statements, Captions [Line Items]
Debt issued					$ 500,000,000
Stated interest rate (as a percent)	4.50%				4.50%
Senior Notes | 2.95% Senior Notes due 2027
Condensed Financial Statements, Captions [Line Items]
Debt issued						$ 500,000,000
Stated interest rate (as a percent)	2.95%					2.95%
Senior Notes | 4.0% Senior Notes due 2025
Condensed Financial Statements, Captions [Line Items]
Debt issued								$ 700,000,000
Stated interest rate (as a percent)	4.00%							4.00%
Senior Notes | 2.5% Senior Notes due 2018
Condensed Financial Statements, Captions [Line Items]
Debt issued							$ 400,000,000
Stated interest rate (as a percent)							2.50%
Senior Notes | 4.4% Senior Notes, due 2026
Condensed Financial Statements, Captions [Line Items]
Debt issued	$ 900,000,000						$ 900,000,000
Stated interest rate (as a percent)	4.40%						4.40%
Senior Notes | 1.25% Senior Notes due 2030
Condensed Financial Statements, Captions [Line Items]
Debt issued		$ 600,000,000
Stated interest rate (as a percent)	1.25%	1.25%
Senior Notes | 2.3% Senior Notes due 2060
Condensed Financial Statements, Captions [Line Items]
Debt issued		$ 700,000,000
Stated interest rate (as a percent)	2.30%	2.30%