Selected Balance Sheet Data (Tables)

3 Months Ended

Mar. 31, 2021

Balance Sheet Related Disclosures [Abstract]

Accounts Receivable, Net

(Millions of dollars)	March 31, 2021		Dec. 31, 2020
Accounts receivable, net
Accounts receivable	$	75	$	78
Less allowance for bad debts	(9)		(8)
Accounts receivable, net	$	66	$	70

Inventories

(Millions of dollars)	March 31, 2021		Dec. 31, 2020
Inventories
Materials and supplies	$	7	$	7
Fuel	5		4
Natural gas	1		4
Total inventories	$	13	$	15

Property, Plant and Equipment, Net

(Millions of dollars)	March 31, 2021		Dec. 31, 2020
Property, plant and equipment, net
Electric plant	$	3,221	$	3,197
Natural gas plant	394		391
Common and other property	224		221
Construction work in progress	83		71
Total property, plant and equipment	3,922		3,880
Less accumulated depreciation	(1,417)		(1,396)
Property, plant and equipment, net	$	2,505	$	2,484