Debt - Summary of Debt (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Principal	$ 3,650	$ 2,700
Unamortized discount and deferred financing costs	(45)	(25)
Total net carrying amount	$ 3,605	$ 2,675
Unsecured Notes \| 2021 Notes
Debt Instrument [Line Items]
Interest Rate		2.30%
Principal		$ 650
Unsecured Notes \| 2021 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes		$ 653
Unsecured Notes \| 2022 Notes
Debt Instrument [Line Items]
Interest Rate		2.60%
Principal		$ 400
Unsecured Notes \| 2022 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes		$ 405
Unsecured Notes \| 2026 Notes
Debt Instrument [Line Items]
Interest Rate	3.40%	3.40%
Principal	$ 850	$ 850
Unsecured Notes \| 2026 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes	$ 970	$ 893
Unsecured Notes \| 2027 Notes
Debt Instrument [Line Items]
Interest Rate	3.40%	3.40%
Principal	$ 400	$ 400
Unsecured Notes \| 2027 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes	$ 454	$ 417
Unsecured Notes \| 2030 Notes
Debt Instrument [Line Items]
Interest Rate	1.35%
Principal	$ 500
Unsecured Notes \| 2030 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes	$ 490
Unsecured Notes \| 2047 Notes
Debt Instrument [Line Items]
Interest Rate	4.50%	4.50%
Principal	$ 400	$ 400
Unsecured Notes \| 2047 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes	$ 525	$ 456
Unsecured Notes \| 2050 Notes
Debt Instrument [Line Items]
Interest Rate	2.50%
Principal	$ 1,500
Unsecured Notes \| 2050 Notes \| Fair Value (Level 2)
Debt Instrument [Line Items]
Fair value of notes	$ 1,462

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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