Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of Property, Plant and Equipment

Property, plant and equipment consisted of the following assets:

(millions)	Estimated Useful Lives	December 31, 2021			December 31, 2020
Electric generation	21-56 years	$	5,395		$	5,694
Electric transmission	28-77 years		1,068			1,008
Electric distribution	14-56 years		3,064			2,859
Gas transmission and distribution	16-77 years		2,360			2,076
General plant and other	8-43 years		946			723
Total cost			12,833			12,360
Less accumulated depreciation			(3,601	)		(3,712	)
Construction work in progress			1,370			1,472
Total property, plant and equipment, net		$	10,602		$	10,120