Asset Retirement Obligations Asset Retirement Obligations (Tables)

12 Months Ended

Sep. 30, 2021

Asset Retirement Obligation Disclosure [Abstract]


Asset Retirement Obligation Activity
	Nuclear		Non-Nuclear		Total
Balance at September 30, 2019	$	3,136	$	2,480	$	5,616
Settlements	(1)		(113)		(114)
Revisions in estimate	—		1,077		1,077


Accretion (recorded as regulatory asset)	143		63		206

Balance at September 30, 2020	3,278		3,507		6,785		(1)

Settlements	(11)		(231)		(242)
Revisions in estimate	12		191		203
Additional obligations	—		43		43

Accretion (recorded as regulatory asset)	149		64		213

Balance at September 30, 2021	$	3,428	$	3,574	$	7,002	(1)

Note

(1) Includes $266 million and $345 million at September 30, 2021 and 2020, respectively, in Current liabilities.

TVA implemented revised depreciation rates during the first quarter of 2022 applicable to its completed plant as a result of the completion of a new depreciation study. The study includes a decline in the service life estimates of TVA’s coal-fired plants based on current planning assumptions to potentially retire the remainder of the coal-fired fleet by 2035. As a result of the accelerated retirements reflected in the depreciation study, TVA performed an assessment of the assumptions used in the timing of cash flows related to its non-nuclear AROs. Based on the assessment, TVA identified changes to its projections of timing of certain asset retirement processes, that will be recorded in 2022.