Segment Reporting Segment Reporting - Condensed Balance Sheet - By Segment (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Assets	$ 25,154	$ 25,436
Liabilities	21,848	22,139
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Assets	7,401	7,458
Liabilities	11,431	11,780
Intersegment Elimination
Segment Reporting Information [Line Items]
Assets	(3,007)	(3,032)
Liabilities	133	108
Las Vegas, NV [Member] \| Operating Segments
Segment Reporting Information [Line Items]
Assets	14,100	14,145
Liabilities	5,294	5,239
Other U.S. [Member] \| Operating Segments
Segment Reporting Information [Line Items]
Assets	6,660	6,865
Liabilities	$ 4,990	$ 5,012

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19-26)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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