In connection with the 2018 sale of our gas trading and storage businesses, we recorded a loss from held for sale measurement of $16 million and $642 million, respectively, for the years ended December 31, 2018 and 2017, which is included in “Loss from assets held for sale” in our consolidated statements of income.

Other income (expense) for the years ended December 31, 2019, 2018 and 2017 consisted of:



Years ended December 31,	2019			2018			2017
(Millions)
Gain on sale of assets (a)	$	148		$	10		$	—
Allowance for funds used during construction	46			30			36
Carrying costs on regulatory assets	21			21			11
Non-service component of net periodic benefit cost	(79		)	(128		)	(120		)
Other	(17		)	1			11
Total Other Income (Expense)	$	119		$	(66	)	$	(62	)

(a) 2019 includes a $134 million gain from the sale of 50% of our interest in the Poseidon projects, and 2018 includes a $10 million gain from the sale of our interest in Coyote Ridge (see Note 22).



As of December 31,	2019			2018
(Millions)
Trade receivables	$	1,151		$	1,204
Allowance for bad debts	(69		)	(62		)
Total Accounts Receivable	$	1,082		$	1,142

The allowance for bad debts relates entirely to gas and electricity consumers and comprises an amount that has been reserved following historical averages of loss percentages.

The change in the allowance for bad debts as of December 31, 2019 and 2018 consisted of:



(Millions)
As of December 31, 2016	$	64
Current period provision	69
Write-off as uncollectible	(69		)
As of December 31, 2017	$	64
Current period provision	74
Write-off as uncollectible	(76		)
As of December 31, 2018	$	62
Current period provision	92
Write-off as uncollectible	(85		)
As of December 31, 2019	$	69

DPA receivable balances were $65 million and $62 million as of December 31, 2019 and 2018, respectively.

Prepayments and other current assets as of December 31, 2019 and 2018 consisted of:



As of December 31,	2019		2018
(Millions)
Prepaid other taxes	$	123	$	137
Broker margin and collateral accounts	33		37
Other pledged deposits	3		6
Prepaid expenses	34		43
Other	6		6
Total	$	199	$	229

Other current liabilities as of December 31, 2019 and 2018 consisted of:



As of December 31,	2019		2018
(Millions)
Advances received	$	140	$	129
Accrued salaries	89		81
Short-term environmental provisions	40		60
Collateral deposits received	44		42
Pension and other postretirement	5		5
Finance leases	9		—
Other	7		10
Total	$	334	$	327