Regulatory Assets and Liabilities

9 Months Ended

Jun. 30, 2016

Regulatory Assets and Liabilities Disclosure [Abstract]

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 deferrals 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
	At June 30, 2016		At September 30, 2015
Current regulatory assets
Deferred nuclear generating units	$	237	$	237
Unrealized losses on commodity derivatives	160		162
Fuel cost adjustment receivable	119		15
Environmental agreements	43		47
Environmental cleanup costs - Kingston ash spill	43		43
Other current regulatory assets	2		2
Total current regulatory assets	604		506

Non-current regulatory assets
Deferred pension costs and other post-retirement benefits costs	5,541		5,565
Unrealized losses on interest rate derivatives	1,521		1,236
Nuclear decommissioning costs	972		1,003
Deferred nuclear generating units	901		1,042
Non-nuclear decommissioning costs	810		828
Environmental cleanup costs - Kingston ash spill	309		348
Unrealized losses on commodity derivatives	87		63
Environmental agreements	25		55
Other non-current regulatory assets	258		278
Total non-current regulatory assets	10,424		10,418
Total regulatory assets	$	11,028	$	10,924

Current regulatory liabilities
Fuel cost adjustment tax equivalents	$	141	$	164
Unrealized gains on commodity derivatives	8		—
Total current regulatory liabilities	149		164

Non-current regulatory liabilities
Unrealized gains on commodity derivatives	4		2
Total non-current regulatory liabilities	4		2
Total regulatory liabilities	$	153	$	166