Receivables (Tables)

12 Months Ended

Dec. 31, 2020

Transfers and Servicing [Abstract]

Schedule of Allowance for Doubtful Accounts

The following table details the changes in the allowance for doubtful accounts related to customer receivables and other receivables:

	Customer receivables						Other receivables
	2020		2019		2018		2020		2019		2018
Balance at beginning of year	$	1	$	1	$	3	$	15	$	15	$	15
Provision for doubtful accounts	1		2		—		3		7		2
Write off of uncollectible accounts	—		(1)		(2)		(1)		(2)		(1)
Recoveries of prior write-offs	—		—		—		(1)		(3)		(3)
Other	(1)		(1)		—		3		(2)		2
Balance at end of year	$	1	$	1	$	1	$	19	$	15	$	15