Stockholders' Equity and Loss Per Share Additional Information (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Aug. 10, 2018	May 02, 2018
Stockholders Equity Noncontrolling Interests and Income (Loss) Per Share [Abstract]
Stock Repurchase Program, Authorized Amount				$ 750	$ 500
Treasury Stock, Shares, Acquired	31
Repurchase of common stock	$ 311	$ 0	$ 0

Number of shares that have been repurchased during the period and are being held in treasury.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration