v3.19.1

Use of Collateral (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
--- | --- | ---
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |  |
Margin Deposit Assets | [1] | $ 343 | $ 221
Natural gas and power prepayments |  | 31 | 23
Total margin deposits and natural gas and power prepayments with our counterparties | [2] | 374 | 244
Letters of credit issued |  | 1,166 | 885
First priority liens under power and natural gas agreements |  | 92 | 102
First priority liens under interest rate hedging instruments |  | 10 | 31
Letters of Credit Issued and First Priority Liens Under Power Natural Gas And Interest Rate Hedging Instruments |  | 1,268 | 1,018
Margin deposits posted with us by our counterparties | [1],[3] | 52 | 4
Letters of credit posted with us by our counterparties |  | 27 | 30
Total margin deposits and letters of credit posted with us by our counterparties |  | 79 | 34
Prepaid Expenses and Other Current Assets [Member] |  |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |  |
Total margin deposits and natural gas and power prepayments with our counterparties |  | 286 | 171
Other Assets [Member] |  |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |  |
Total margin deposits and natural gas and power prepayments with our counterparties |  | 9 | 9
Current and Non-current Derivative Assets and Liabilities [Member] |  |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |  |
Total margin deposits and natural gas and power prepayments with our counterparties |  | 79 | 64
Margin deposits posted with us by our counterparties |  | 32 | 2
Other Current Liabilities [Member] |  |  |
Financial Instruments Owned and Pledged as Collateral [Line Items] |  |  |
Margin deposits posted with us by our counterparties |  | $ 20 | $ 2
[1] | We offset fair value amounts recognized for derivative instruments executed with the same counterparty under a master netting arrangement for financial statement presentation; therefore, amounts recognized for the right to reclaim, or the obligation to return, cash collateral are presented net with the corresponding derivative instrument fair values. See Note 10 for further discussion of our derivative instruments subject to master netting arrangements.
[2] | At December 31, 2018 and 2017, $79 million and $64 million, respectively, were included in current and long-term derivative assets and liabilities, $286 million and $171 million, respectively, were included in margin deposits and other prepaid expense and $9 million and $9 million, respectively, were included in other assets on our Consolidated Balance Sheets.
[3] | At December 31, 2018 and 2017, $32 million and $2 million, respectively, were included in current and long-term derivative assets and liabilities and $20 million and $2 million, respectively, were included in other current liabilities on our Consolidated Balance Sheets.

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- Definition The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8,17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition This element represents money paid in advance to protect the provider of a product or service, such as a lessor, against damage or nonpayment by the buyer or tenant (lessee) during the term of the agreement. Such damages may include physical damage to the property, theft of property, and other contractual breaches. Security deposits held may be interest or noninterest bearing. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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