Stock-based Compensation (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs and PSUs	$ 37	$ 41	$ 125	$ 126
Stock options	4	6	15	22
Stock-based compensation expense, before income taxes	46	65	191	171
Related tax benefit	(10)	(12)	(37)	(36)
Stock-based compensation expense, net of tax benefit	36	53	154	135
SG&A Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	41	47	140	148
Restructuring and Other Corporate Matters [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense, before income taxes	$ 5	$ 18	$ 51	$ 23

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
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Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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Amount of noncash expense for share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 230
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-Section 45
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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 noncash expense for option under share-based payment arrangement.

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