Selected Balance Sheet Data (Tables)

6 Months Ended

Jun. 30, 2020

Balance Sheet Related Disclosures [Abstract]

Accounts Receivable, Net

(Millions of Dollars)	June 30, 2020		Dec. 31, 2019
Accounts receivable, net
Accounts receivable	$	366.0	$	382.8
Less allowance for bad debts	(23.4)		(23.0)
Accounts receivable, net	$	342.6	$	359.8

Inventories

(Millions of Dollars)	June 30, 2020		Dec. 31, 2019
Inventories
Materials and supplies	$	179.9	$	175.6
Fuel	95.1		103.2
Natural gas	10.7		26.0
Total Inventories	$	285.7	$	304.8

Property, plant and equipment, net

(Millions of Dollars)	June 30, 2020		Dec. 31, 2019
Property, plant and equipment
Electric plant	$	19,054.8	$	18,519.5
Natural gas plant	1,593.2		1,562.9
Common and other property	908.2		886.7
Construction work in progress	885.4		846.3
Total property, plant and equipment	22,441.6		21,815.4
Less accumulated depreciation	(8,181.0)		(7,945.3)
Nuclear fuel	2,924.8		2,909.8
Less accumulated amortization	(2,600.6)		(2,535.9)
Property, plant and equipment, net	$	14,584.8	$	14,244.0