Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2020

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets

Components of regulatory assets:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2020				Dec. 31, 2019
Regulatory Assets			Current		Noncurrent		Current		Noncurrent
Pension and retiree medical obligations	9	Various	$	12	$	178	$	11	$	204
Excess deferred taxes — TCJA	7	Various	3		51		2		52
Recoverable deferred taxes on AFUDC		Plant lives	—		42		—		34
Net AROs (a)	1, 10	Various	—		33		—		27
Losses on reacquired debt		Term of related debt	1		20		1		21
Texas revenue surcharge		One to two years	54		17		2		—
Conservation programs (b)	1	One to two years	1		2		1		1
Other		Various	5		14		3		25
Total regulatory assets			$	76	$	357	$	20	$	364

(a)Includes amounts recorded for future recovery of AROs.

(b)Includes costs for conservation programs, as well as incentives allowed in certain jurisdictions.

Regulatory Liabilities

Components of regulatory liabilities:

(Millions of Dollars)	See Note(s)	Remaining Amortization Period	Dec. 31, 2020				Dec. 31, 2019
Regulatory Liabilities			Current		Noncurrent		Current		Noncurrent
Deferred income tax adjustments and TCJA refunds (a)	7	Various	$	6	$	513	$	7	$	535
Plant removal costs	1, 10	Various	—		177		—		175
Revenue subject to refund		One to two years	4		4		14		1
Gain from asset sales		Various	—		2		—		2
Deferred electric energy costs		Less than one year	35		—		82		—
Contract valuation adjustments (b)	1, 8	Less than one year	7		—		12		—
Other		Various	5		22		3		19
Total regulatory liabilities (c)			$	57	$	718	$	118	$	732

(a)Includes the revaluation of recoverable/regulated plant ADIT and revaluation impact of non-plant ADIT due to the TCJA.

(b)Includes the fair value of certain long-term PPAs used to meet energy capacity requirements.

(c)Revenue subject to refund of $4 million for 2019 was included in other current liabilities and none for 2020.