Schedule II—Valuation and Qualifying Accounts The tables below detail the activity of the customer receivable reserve, insurance liability, and the valuation allowance on deferred tax assets for the years ended December 31, 2020, 2021, and 2022 (in millions): | | | | | | | | | | | | | | | | | Balance at
Beginning of
Year | Charged to
Expenses | Charges
Utilized/
Write-Offs | Balance at
End of Year | | Customer Receivable Reserve | | | | | | | | | | | Year Ended December 31, 2020 | $ | 51 | | $ | 108 | | $ | (68) | | $ | 91 | | | Year Ended December 31, 2021 | $ | 91 | | $ | 27 | | $ | (87) | | $ | 31 | | | Year Ended December 31, 2022 | $ | 31 | | $ | 49 | | $ | (41) | | $ | 39 | |
| | | | | | | | | | | | | | | | | | | Balance at
Beginning of
Year | Additions for
Current Period | Changes in
Estimates for
Prior Periods | Net Payments | Balance at
End of Year | | Insurance Liability | | | | | | | | | | | | | Year Ended December 31, 2020 | $ | 73 | | $ | 98 | | $ | (21) | | $ | (99) | | $ | 51 | | | Year Ended December 31, 2021 | $ | 51 | | $ | 85 | | $ | 1 | | $ | (90) | | $ | 47 | | | Year Ended December 31, 2022 | $ | 47 | | $ | 140 | | $ | (5) | | $ | (121) | | $ | 61 | |
| | | | | | | | | | | | | | | | Balance at
Beginning of
Year | Charged
(Credited) to
Expenses | Charged to
Other
Accounts | Balance at
End of Year | | Valuation Allowance on Deferred Tax Assets | | | | | | | | | | | Year Ended December 31, 2020 | $ | 1,024 | | $ | 1,029 | | $ | — | | $ | 2,053 | | | Year Ended December 31, 2021 | $ | 2,053 | | $ | 1,211 | | $ | — | | $ | 3,264 | | | Year Ended December 31, 2022 | $ | 3,264 | | $ | (98) | | $ | — | | $ | 3,166 | |
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