Accounts Receivable (Accounts Receivable) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts Receivable [Abstract]
Retail and wholesale	$ 625	$ 678
Other	71	71
Less: Allowance for doubtful accounts	(100)	(120)
Accounts receivable, net	$ 596	$ 629

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant