Long-term Debt and Finance Leases - Annual Payments Based on the Maturities of Debt and Capital Leases (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
2021	$ 1
2022	2
2023	1
2024	600
2025	500
Thereafter	7,755
Subtotal long-term debt and finance leases (including current maturities)	$ 8,859	$ 6,042

Amount of short-term and long-term debt and lease obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04.(a))
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-Topic 470
-SubTopic 10
-Section 50
-Paragraph 1
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