Debt - Summary (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt	$ 4,111	$ 4,110
Senior Notes \| 4.0% Senior Notes due 2025
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.00%
Long-term debt	$ 695	695
Unamortized debt discount and issuance costs	$ 5
Senior Notes \| 2.95% Senior Notes due 2027
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.95%
Long-term debt	$ 495	495
Unamortized debt discount and issuance costs	$ 5
Senior Notes \| 2.5% Senior Notes due 2029
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.50%
Long-term debt	$ 496	495
Unamortized debt discount and issuance costs	$ 4
Senior Notes \| 1.25% Senior Notes due 2030
Debt Instrument [Line Items]
Stated interest rate (as a percent)	1.25%
Long-term debt	$ 592	592
Unamortized debt discount and issuance costs	$ 8
Senior Notes \| 6.55% Senior Notes due 2037
Debt Instrument [Line Items]
Stated interest rate (as a percent)	6.55%
Long-term debt	$ 290	290
Unamortized debt discount and issuance costs	$ 3
Senior Notes \| 4.5% Senior Notes due 2048
Debt Instrument [Line Items]
Stated interest rate (as a percent)	4.50%
Long-term debt	$ 273	273
Unamortized debt discount and issuance costs	$ 10
Senior Notes \| 3.25% Senior Notes due 2049
Debt Instrument [Line Items]
Stated interest rate (as a percent)	3.25%
Long-term debt	$ 589	589
Unamortized debt discount and issuance costs	$ 11
Senior Notes \| 2.3% Senior Notes due 2060
Debt Instrument [Line Items]
Stated interest rate (as a percent)	2.30%
Long-term debt	$ 681	$ 681
Unamortized debt discount and issuance costs	$ 19

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

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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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