Debt - Summary of Debt (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total gross long-term debt	$ 3,650	$ 3,650
Unamortized discount and deferred financing costs	(44)	(45)
Total net carrying amount	$ 3,606	$ 3,605
Unsecured Debt \| Unsecured 2026 Notes
Debt Instrument [Line Items]
Interest rate	3.40%	3.40%
Total gross long-term debt	$ 850	$ 850
Unsecured Debt \| Unsecured 2026 Notes \| Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Fair Value (Level 2)	$ 930	$ 970
Unsecured Debt \| Unsecured 2027 Notes
Debt Instrument [Line Items]
Interest rate	3.40%	3.40%
Total gross long-term debt	$ 400	$ 400
Unsecured Debt \| Unsecured 2027 Notes \| Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Fair Value (Level 2)	$ 438	$ 454
Unsecured Debt \| Unsecured 2030 Notes
Debt Instrument [Line Items]
Interest rate	1.35%	1.35%
Total gross long-term debt	$ 500	$ 500
Unsecured Debt \| Unsecured 2030 Notes \| Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Fair Value (Level 2)	$ 450	$ 490
Unsecured Debt \| Unsecured 2047 Notes
Debt Instrument [Line Items]
Interest rate	4.50%	4.50%
Total gross long-term debt	$ 400	$ 400
Unsecured Debt \| Unsecured 2047 Notes \| Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Fair Value (Level 2)	$ 469	$ 525
Unsecured Debt \| Unsecured 2050 Notes
Debt Instrument [Line Items]
Interest rate	2.50%	2.50%
Total gross long-term debt	$ 1,500	$ 1,500
Unsecured Debt \| Unsecured 2050 Notes \| Significant Other Observable Inputs (Level 2)
Debt Instrument [Line Items]
Fair Value (Level 2)	$ 1,258	$ 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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