Stock Compensation Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Share-Based Payment Arrangement [Abstract]
Restricted stock units	$ 28	$ 30	$ 54	$ 66
Stock options	5	5	10	11
Employee stock purchase plan	2	2	5	4
Stock-based compensation expense	35	37	69	81
Tax benefit	(4)	(4)	(8)	(9)
Stock-based compensation expense (net of tax)	$ 31	$ 33	$ 61	$ 72

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Amount, after tax, of expense for award under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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The amount of plan compensation cost recognized during the period.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=109244661&loc=d3e17540-113929

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Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3602-108585

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Amount of noncash expense for option under share-based payment arrangement.

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