The table below summarizes the balances outstanding under margin deposits, natural gas and power prepayments, and exposure under letters of credit and first priority liens for commodity procurement and risk management activities as of December 31, 2015 and 2014 (in millions):



	2015		2014
Margin deposits⁽¹⁾	$	89	$	96
Natural gas and power prepayments	34		22
Total margin deposits and natural gas and power prepayments with our counterparties⁽²⁾	$	123	$	118

Letters of credit issued	$	600	$	450
First priority liens under power and natural gas agreements⁽³⁾	382		48
First priority liens under interest rate swap agreements	92		116
Total letters of credit and first priority liens with our counterparties	$	1,074	$	614

Margin deposits posted with us by our counterparties⁽¹⁾⁽⁴⁾	$	35	$	47
Letters of credit posted with us by our counterparties	24		61
Total margin deposits and letters of credit posted with us by our counterparties	$	59	$	108

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(1)

Balances are subject to master netting arrangements and presented on a gross basis on our Consolidated Balance Sheets. We do not offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation, and we do not offset amounts recognized for the right to reclaim, or the obligation to return, cash collateral with corresponding derivative instrument fair values. See Note 8 for further discussion of our derivative instruments subject to master netting arrangements.


(2)	At December 31, 2015 and 2014, $101 million and $109 million, respectively, were included in margin deposits and other prepaid expense and $22 million and $9 million, respectively, were included in other assets on our Consolidated Balance Sheets.


(3)	Includes $345 million related to first priority liens under power supply contracts associated with our retail hedging activities.


(4)	Included in other current liabilities on our Consolidated Balance Sheets.