Regulatory Assets and Liabilities

Regulatory assets generally represent incurred costs that have been deferred because such costs are probable of future recovery in customer rates. Regulatory liabilities generally represent obligations to make refunds to customers for previous collections for costs that are not likely to be incurred or deferral of gains that will be credited to customers in future periods. Components of regulatory assets and regulatory liabilities are summarized in the table below:



Regulatory Assets and Liabilities⁽¹⁾
	At March 31, 2020		At September 30, 2019
Current regulatory assets
Unrealized losses on interest rate derivatives	$	109	$	89
Unrealized losses on commodity derivatives	52		39
Fuel cost adjustment receivable	—		28
Total current regulatory assets	161		156

Non-current regulatory assets
Deferred pension costs and other post-retirement benefits costs	4,602		4,756
Non-nuclear decommissioning costs	1,859		1,741
Nuclear decommissioning costs	1,200		868
Unrealized losses on interest rate derivatives	1,615		1,241
Unrealized losses on commodity contracts	8		15
Other non-current regulatory assets	149		142
Total non-current regulatory assets	9,433		8,763
Total regulatory assets	$	9,594	$	8,919

Current regulatory liabilities
Fuel cost adjustment tax equivalents	$	131	$	138
Fuel cost adjustment	72		—
Unrealized gains on commodity derivatives	4		12
Total current regulatory liabilities	$	207	$	150

Note

(1) Amounts for Non-current regulatory liabilities were less than $1 million at March 31, 2020, and September 30, 2019, and are therefore not represented in the table above.

Due to recent higher volatility in the financial markets associated with the COVID-19 pandemic, TVA experienced unrealized losses related to its investment portfolios and derivative instruments for the six months ended March 31, 2020. TVA does not recognize unrealized gains and losses from the investment portfolios and derivative instruments within earnings but rather defers all such gains and losses within a regulatory liability or asset in accordance with its accounting policy. See Note 14 — Risk Management Activities and Derivative Transactions and Note 15 — Fair Value Measurements.