Income Taxes And Tax-Related Items Reconciliation of the Beginning and Ending Amounts of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Balance at January 1	$ 22	$ 14	$ 11
Increases as a result of tax positions taken during a prior period	0	8	3
Decrease related to settlements with tax authorities	(7)	0	0
Balance at December 31	$ 15	$ 22	$ 14

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- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=65882285&loc=SL6600010-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Unrecognized Tax Benefit
-URI http://asc.fasb.org/extlink&oid=6527854

+ Details

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- Definition

Amount of decrease in unrecognized tax benefits resulting from settlements with taxing authorities.

+ References

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- Definition

Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

+ References

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