Leases - Additional Information (Details) - USD ($) $ in Millions	2 Months Ended	10 Months Ended	12 Months Ended
Dec. 31, 2017	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating leases, rent expense	$ 95	$ 447	$ 412	$ 524
Sublease rental income	2	7	9	9
Gross rental expense	$ 28	$ 138	$ 798	$ 192
Sublease rental income (as a percent)	2.00%	2.00%	10.00%	2.00%

Amount of operating lease income from lease payments and variable lease payments paid and payable to lessor. Includes, but is not limited to, variable lease payments not included in measurement of lease receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=119202524&loc=SL77919372-209981

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=77888421&loc=SL77919311-209978

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 270
-SubTopic 10
-Section 50
-Paragraph 6A
-URI http://asc.fasb.org/extlink&oid=118952077&loc=SL77927221-108306

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration