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Receivables - Schedule of Allowance for Doubtful Accounts (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Customer receivables |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |
Balance at beginning of year | $ 1 | $ 1 | $ 3
Provision for doubtful accounts | 1 | 2 | 0
Write off of uncollectible accounts | 0 | (1) | (2)
Recoveries of prior write-offs | 0 | 0 | 0
Other | (1) | (1) | 0
Balance at end of year | 1 | 1 | 1
Other receivables |  |  |
Accounts Receivable, Allowance for Credit Loss [Roll Forward] |  |  |
Balance at beginning of year | 15 | 15 | 15
Provision for doubtful accounts | 3 | 7 | 2
Write off of uncollectible accounts | (1) | (2) | (1)
Recoveries of prior write-offs | (1) | (3) | (3)
Other | 3 | (2) | 2
Balance at end of year | $ 19 | $ 15 | $ 15

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- Definition Allowance for doubtful accounts other + References No definition available. + Details
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Balance Type: | credit
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- Definition Allowance for doubtful accounts receivable, recoveries adjustments. + References No definition available. + Details
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- Definition Amount of allowance for credit loss on accounts receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5074-111524 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=121599878&loc=SL82895884-210446 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of direct write-downs of accounts receivable charged against the allowance. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 + Details
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- Definition Amount of expense (reversal of expense) for expected credit loss on accounts receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919249-210447 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(5)) -URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227 + Details
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