Schedule II, Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2020

SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]

Schedule II, Valuation and Qualifying Accounts

NSP-Wisconsin and Subsidiaries Valuation and Qualifying Accounts Years Ended Dec. 31

	Allowance for bad debts
(Millions of Dollars)	2021		2020		2019
Balance at Jan. 1	$	8	$	6	$	6
Additions charged to costs and expenses	4		7		7
Additions charged to other accounts (a)	1		1		2
Deductions from reserves (b)	(5)		(6)		(9)
Balance at Dec. 31	$	8	$	8	$	6

(a)Recovery of amounts previously written-off.

(b)Deductions related primarily to bad debt write-offs.