Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2020

Regulatory Assets [Line Items]

Schedule of Regulatory Liabilities [Table Text Block]

Regulatory assets and liabilities consist of the following (dollars in millions):

	Remaining Amortization Period	As of December 31,
		2020						2019
		Earning a Return (1)		Not Earning a Return		Total		Total
Regulatory assets:
Price risk management	2035	$	—	$	124	$	124	$	95
Pension plan	(2)	—		240		240		213
Debt issuance costs	2050	—		25		25		26
Trojan decommissioning activities	2059	—		95		95		94
Other	Various	87		22		109		72
Total regulatory assets		$	87	$	506	$	593	$	500
Regulatory liabilities:
Asset retirement removal costs	(3)	$	1,016	$	—	$	1,016	$	1,021
Deferred income taxes	(4)	239		—		239		260
Asset retirement obligations	(3)	37		—		37		54
Tax reform deferral (5)	2020	—		—		—		23
Price risk management	2021	—		18		18		2
Other	Various	46		36		82		61
Total regulatory liabilities		$	1,338	$	54	$	1,392	$	1,421

(1)Earning a return includes either interest on the regulatory asset or liability, or inclusion of the regulatory asset or liability as an increase or decrease to rate base at the allowed rate of return.

(2)Recovery expected over the average service life of employees.

(3)Recovery or refund expected over the estimated lives of the underlying assets and treated as a reduction to rate base.

(4)Refund expected primarily through amortization using the average rate assumption method over the average life of the underlying assets and treated as a reduction to rate base.

(5)Refund related to the deferral of the 2018 net tax benefits due to the change in corporate tax rate under TCJA, including interest, over a two-year period that began in 2019.

Schedule of Regulatory Assets [Table Text Block]

Regulatory assets and liabilities consist of the following (dollars in millions):

	Remaining Amortization Period	As of December 31,
		2020						2019
		Earning a Return (1)		Not Earning a Return		Total		Total
Regulatory assets:
Price risk management	2035	$	—	$	124	$	124	$	95
Pension plan	(2)	—		240		240		213
Debt issuance costs	2050	—		25		25		26
Trojan decommissioning activities	2059	—		95		95		94
Other	Various	87		22		109		72
Total regulatory assets		$	87	$	506	$	593	$	500
Regulatory liabilities:
Asset retirement removal costs	(3)	$	1,016	$	—	$	1,016	$	1,021
Deferred income taxes	(4)	239		—		239		260
Asset retirement obligations	(3)	37		—		37		54
Tax reform deferral (5)	2020	—		—		—		23
Price risk management	2021	—		18		18		2
Other	Various	46		36		82		61
Total regulatory liabilities		$	1,338	$	54	$	1,392	$	1,421

(1)Earning a return includes either interest on the regulatory asset or liability, or inclusion of the regulatory asset or liability as an increase or decrease to rate base at the allowed rate of return.

(2)Recovery expected over the average service life of employees.

(3)Recovery or refund expected over the estimated lives of the underlying assets and treated as a reduction to rate base.

(4)Refund expected primarily through amortization using the average rate assumption method over the average life of the underlying assets and treated as a reduction to rate base.

(5)Refund related to the deferral of the 2018 net tax benefits due to the change in corporate tax rate under TCJA, including interest, over a two-year period that began in 2019.