Selected Balance Sheet Data (Tables)

9 Months Ended

Sep. 30, 2021

Balance Sheet Related Disclosures [Abstract]

Accounts Receivable, Net

(Millions of dollars)	Sept. 30, 2021		Dec. 31, 2020
Accounts receivable, net
Accounts receivable	$	68	$	78
Less allowance for bad debts	(8)		(8)
Accounts receivable, net	$	60	$	70

Inventories

(Millions of dollars)	Sept. 30, 2021		Dec. 31, 2020
Inventories
Materials and supplies	$	7	$	7
Fuel	6		4
Natural gas	10		4
Total inventories	$	23	$	15

Property, Plant and Equipment, Net

(Millions of dollars)	Sept. 30, 2021		Dec. 31, 2020
Property, plant and equipment, net
Electric plant	$	3,287	$	3,197
Natural gas plant	411		391
Common and other property	226		221
Construction work in progress	122		71
Total property, plant and equipment	4,046		3,880
Less accumulated depreciation	(1,456)		(1,396)
Property, plant and equipment, net	$	2,590	$	2,484