Equity (Unrecognized Compensation Expense Related to Stock-Based Compensation) (Details) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($)
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	$ 3
Weighted Average Period	1 year 8 months 26 days
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	$ 31
Weighted Average Period	1 year 8 months 8 days
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense	$ 39
Weighted Average Period	1 year 10 months 28 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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 (i)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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