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Valuation and Qualifying Accounts
12 Months Ended
Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]  
Valuation and Qualifying Accounts Valuation and Qualifying Accounts
The table below provides changes in the allowance for credit losses over each period:
(in millions)202020192018
Balance at beginning of year$25 $25 $25 
Additions charged to expense25 
Deductions/other(12)(3)(5)
Balance at end of year$38 $25 $25