Stock Compensation Plans - Stock Compensation Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Payment Arrangement [Abstract]
Stock-based compensation plans expense	$ 125	$ 130	$ 116
Income tax benefit	(21)	(27)	(41)
Excess tax benefit on awards vested, exercised and expired	(6)	(5)	(15)
Total stock-based compensation plans expense, after-tax	$ 98	$ 98	$ 60

Employee Service Share-based Compensation, Excess Tax Benefit from Compensation Expense

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
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-SubTopic 10
-Section S99
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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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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