Fair Value Measurements (Tables)
|
12 Months Ended |
Dec. 31, 2017 |
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | Net Asset Value as a Practical Expedient | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 331 |
| | $ | 239 |
| | $ | — |
| | $ | — |
| | $ | 570 |
| Interest rate derivatives | — |
| | 1 |
| | — |
| | — |
| | 1 |
| Foreign currency derivatives | — |
| | 129 |
| | — |
| | — |
| | 129 |
| Nuclear decommissioning trusts:(c) | | | | | | | | | | Domestic equity | 690 |
| | 82 |
| | — |
| | — |
| | 772 |
| Foreign equity | 62 |
| | 224 |
| | — |
| | — |
| | 286 |
| U.S. Treasury and government agency securities | — |
| | 251 |
| | — |
| | — |
| | 251 |
| Municipal bonds | — |
| | 68 |
| | — |
| | — |
| | 68 |
| Corporate bonds | 21 |
| | 315 |
| | — |
| | — |
| | 336 |
| Mortgage and asset backed securities | — |
| | 57 |
| | — |
| | — |
| | 57 |
| Private equity | — |
| | — |
| | — |
| | 29 |
| | 29 |
| Other | 19 |
| | 12 |
| | — |
| | — |
| | 31 |
| Cash equivalents | 1,455 |
| | — |
| | — |
| | — |
| | 1,455 |
| Other investments | 9 |
| | — |
| | 1 |
| | — |
| | 10 |
| Total | $ | 2,587 |
| | $ | 1,378 |
| | $ | 1 |
| | $ | 29 |
| | $ | 3,995 |
| Liabilities: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 480 |
| | $ | 253 |
| | $ | — |
| | $ | — |
| | $ | 733 |
| Interest rate derivatives | — |
| | 38 |
| | — |
| | — |
| | 38 |
| Foreign currency derivatives | — |
| | 23 |
| | — |
| | — |
| | 23 |
| Contingent consideration | — |
| | — |
| | 22 |
| | — |
| | 22 |
| Total | $ | 480 |
| | $ | 314 |
| | $ | 22 |
| | $ | — |
| | $ | 816 |
|
| | (a) | Energy-related derivatives exclude $11 million associated with premiums and certain weather derivatives accounted for based on intrinsic value rather than fair value. |
| | (b) | Energy-related derivatives exclude cash collateral of $193 million. |
| | (c) | Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, currencies, and payables related to pending investment purchases and the securities lending program. See Note 1 under "Nuclear Decommissioning" for additional information. |
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | Net Asset Value as a Practical Expedient | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 338 |
| | $ | 333 |
| | $ | — |
| | $ | — |
| | $ | 671 |
| Interest rate derivatives | — |
| | 14 |
| | — |
| | — |
| | 14 |
| Nuclear decommissioning trusts:(c) | | | | | | | | | | Domestic equity | 589 |
| | 73 |
| | — |
| | — |
| | 662 |
| Foreign equity | 48 |
| | 168 |
| | — |
| | — |
| | 216 |
| U.S. Treasury and government agency securities | — |
| | 92 |
| | — |
| | — |
| | 92 |
| Municipal bonds | — |
| | 73 |
| | — |
| | — |
| | 73 |
| Corporate bonds | 22 |
| | 310 |
| | — |
| | — |
| | 332 |
| Mortgage and asset backed securities | — |
| | 183 |
| | — |
| | — |
| | 183 |
| Private equity | — |
| | — |
| | — |
| | 20 |
| | 20 |
| Other | 11 |
| | 15 |
| | — |
| | — |
| | 26 |
| Cash equivalents | 1,172 |
| | — |
| | — |
| | — |
| | 1,172 |
| Other investments | 9 |
| | — |
| | 1 |
| | — |
| | 10 |
| Total | $ | 2,189 |
| | $ | 1,261 |
| | $ | 1 |
| | $ | 20 |
| | $ | 3,471 |
| Liabilities: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 345 |
| | $ | 285 |
| | $ | — |
| | $ | — |
| | $ | 630 |
| Interest rate derivatives | — |
| | 29 |
| | — |
| | — |
| | 29 |
| Foreign currency derivatives | — |
| | 58 |
| | — |
| | — |
| | 58 |
| Contingent consideration | — |
| | — |
| | 18 |
| | — |
| | 18 |
| Total | $ | 345 |
| | $ | 372 |
| | $ | 18 |
| | $ | — |
| | $ | 735 |
|
| | (a) | Energy-related derivatives exclude $4 million associated with certain weather derivatives accounted for based on intrinsic value rather than fair value. |
| | (b) | Energy-related derivatives exclude cash collateral of $62 million. |
| | (c) | Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, currencies, and payables related to pending investment purchases and the securities lending program. See Note 1 under "Nuclear Decommissioning" for additional information. |
|
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments |
As of December 31, 2017 and 2016, the fair value measurements of private equity investments held in the nuclear decommissioning trust that are calculated at net asset value per share (or its equivalent) as a practical expedient, as well as the nature and risks of those investments, were as follows: | | | | | | | | | | | | | | Fair Value | | Unfunded Commitments | | Redemption Frequency | | Redemption Notice Period | | (in millions) |
|
|
|
| As of December 31, 2017 | $ | 29 |
|
| $ | 21 |
|
| Not Applicable |
| Not Applicable | As of December 31, 2016 | $ | 20 |
| | $ | 25 |
| | Not Applicable | | Not Applicable |
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt, including securities due within one year: | | | | 2017 | $ | 48,151 |
| | $ | 51,348 |
| 2016 | $ | 45,080 |
| | $ | 46,286 |
|
|
ALABAMA POWER CO |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | Net Asset Value as a Practical Expedient | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 4 |
| | $ | — |
| | $ | — |
| | $ | 4 |
| Nuclear decommissioning trusts:(*) | | | | | | | | | | Domestic equity | 442 |
| | 81 |
| | — |
| | — |
| | 523 |
| Foreign equity | 62 |
| | 59 |
| | — |
| | — |
| | 121 |
| U.S. Treasury and government agency securities | — |
| | 24 |
| | — |
| | — |
| | 24 |
| Corporate bonds | 21 |
| | 160 |
| | — |
| | — |
| | 181 |
| Mortgage and asset backed securities | — |
| | 18 |
| | — |
| | — |
| | 18 |
| Private equity | — |
| | — |
| | — |
| | 29 |
| | 29 |
| Other | 6 |
| | — |
| | — |
| | — |
| | 6 |
| Cash equivalents | 349 |
| | — |
| | — |
| | — |
| | 349 |
| Total | $ | 880 |
| | $ | 346 |
| | $ | — |
| | $ | 29 |
| | $ | 1,255 |
| Liabilities: | | | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 10 |
| | $ | — |
| | $ | — |
| | $ | 10 |
|
| | (*) | Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases. See Note 1 under "Nuclear Decommissioning" for additional information. |
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | Net Asset Value as a Practical Expedient | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 20 |
| | $ | — |
| | $ | — |
| | $ | 20 |
| Nuclear decommissioning trusts:(*) |
|
| |
|
| |
|
| | | |
|
| Domestic equity | 385 |
| | 72 |
| | — |
| | — |
| | 457 |
| Foreign equity | 48 |
| | 47 |
| | — |
| | — |
| | 95 |
| U.S. Treasury and government agency securities | — |
| | 21 |
| | — |
| | — |
| | 21 |
| Corporate bonds | 22 |
| | 146 |
| | — |
| | — |
| | 168 |
| Mortgage and asset backed securities | — |
| | 19 |
| | — |
| | — |
| | 19 |
| Private equity | — |
| | — |
| | — |
| | 20 |
| | 20 |
| Other | — |
| | 10 |
| | — |
| | — |
| | 10 |
| Cash equivalents | 262 |
| | — |
| | — |
| | — |
| | 262 |
| Total | $ | 717 |
| | $ | 335 |
| | $ | — |
| | $ | 20 |
| | $ | 1,072 |
| Liabilities: | | | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 9 |
| | $ | — |
| | $ | — |
| | $ | 9 |
|
| | (*) | Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases. See Note 1 under "Nuclear Decommissioning" for additional information. |
|
Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments |
As of December 31, 2017 and 2016, the fair value measurements of private equity investments held in the nuclear decommissioning trusts that are calculated at net asset value per share (or its equivalent) as a practical expedient, as well as the nature and risks of those investments, were as follows: | | | | | | | | | | | | | | Fair Value | | Unfunded Commitments | | Redemption Frequency | | Redemption Notice Period | | (in millions) | | | | | As of December 31, 2017 | $ | 29 |
| | $ | 21 |
| | Not Applicable | | Not Applicable | As of December 31, 2016 | $ | 20 |
| | $ | 25 |
| | Not Applicable | | Not Applicable |
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt, including securities due within one year: | | | | 2017 | $ | 7,625 |
| | $ | 8,305 |
| 2016 | $ | 7,092 |
| | $ | 7,544 |
|
|
GEORGIA POWER CO |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 6 |
| | $ | — |
| | $ | 6 |
| Nuclear decommissioning trusts:(*) | | | | | | | | Domestic equity | 248 |
| | 1 |
| | — |
| | 249 |
| Foreign equity | — |
| | 166 |
| | — |
| | 166 |
| U.S. Treasury and government agency securities | — |
| | 227 |
| | — |
| | 227 |
| Municipal bonds | — |
| | 68 |
| | — |
| | 68 |
| Corporate bonds | — |
| | 155 |
| | — |
| | 155 |
| Mortgage and asset backed securities | — |
| | 40 |
| | — |
| | 40 |
| Other | 12 |
| | 12 |
| | — |
| | 24 |
| Cash equivalents | 690 |
| | — |
| | — |
| | 690 |
| Total | $ | 950 |
| | $ | 675 |
| | $ | — |
| | $ | 1,625 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 19 |
| | $ | — |
| | $ | 19 |
| Interest rate derivatives | — |
| | 5 |
| | — |
| | 5 |
| Total | $ | — |
| | $ | 24 |
| | $ | — |
| | $ | 24 |
|
| | (*) | Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, currencies, and payables related to pending investment purchases and the securities lending program. See Note 1 under "Nuclear Decommissioning" for additional information. |
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 44 |
| | $ | — |
| | $ | 44 |
| Interest rate derivatives | — |
| | 2 |
| | — |
| | 2 |
| Nuclear decommissioning trusts:(*) | | | | | | | | Domestic equity | 204 |
| | 1 |
| | — |
| | 205 |
| Foreign equity | — |
| | 121 |
|
| — |
| | 121 |
| U.S. Treasury and government agency securities | — |
| | 71 |
| | — |
| | 71 |
| Municipal bonds | — |
| | 73 |
| | — |
| | 73 |
| Corporate bonds | — |
| | 164 |
| | — |
| | 164 |
| Mortgage and asset backed securities | — |
| | 164 |
| | — |
| | 164 |
| Other | 11 |
| | 5 |
| | — |
| | 16 |
| Total | $ | 215 |
| | $ | 645 |
| | $ | — |
| | $ | 860 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 8 |
| | $ | — |
| | $ | 8 |
| Interest rate derivatives | — |
| | 3 |
| | — |
| | 3 |
| Total | $ | — |
| | $ | 11 |
| | $ | — |
| | $ | 11 |
|
| | (*) | Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, currencies, and payables related to pending investment purchases and the securities lending program. See Note 1 under "Nuclear Decommissioning" for additional information. |
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt, including securities due within one year: | | | | 2017 | $ | 11,777 |
| | $ | 12,531 |
| 2016 | $ | 10,516 |
| | $ | 11,034 |
|
|
GULF POWER CO |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Cash equivalents | $ | 21 |
| | $ | — |
| | $ | — |
| | $ | 21 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 21 |
| | $ | — |
| | $ | 21 |
|
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 5 |
| | $ | — |
| | $ | 5 |
| Cash equivalents | 20 |
| | — |
| | — |
| | 20 |
| Total | $ | 20 |
| | $ | 5 |
| | $ | — |
| | $ | 25 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 29 |
| | $ | — |
| | $ | 29 |
|
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt: | | | | 2017 | $ | 1,285 |
| | $ | 1,334 |
| 2016 | $ | 1,074 |
| | $ | 1,097 |
|
|
MISSISSIPPI POWER CO |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 2 |
| | $ | — |
| | $ | 2 |
| Interest rate derivatives | — |
| | 1 |
| | — |
| | 1 |
| Cash equivalents | 224 |
| | — |
| | — |
| | 224 |
| Total | $ | 224 |
| | $ | 3 |
| | $ | — |
| | $ | 227 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 9 |
| | $ | — |
| | $ | 9 |
|
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 3 |
| | $ | — |
| | $ | 3 |
| Interest rate derivatives | — |
| | 3 |
| | — |
| | 3 |
| Cash equivalents | 206 |
| | — |
| | — |
| | 206 |
| Total | $ | 206 |
| | $ | 6 |
| | $ | — |
| | $ | 212 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 10 |
| | $ | — |
| | $ | 10 |
|
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt: | | | | 2017 | $ | 2,086 |
| | $ | 2,076 |
| 2016 | $ | 2,979 |
| | $ | 2,922 |
|
|
SOUTHERN POWER CO |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2017: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 3 |
| | $ | — |
| | $ | 3 |
| Foreign currency derivatives | — |
| | 129 |
| | — |
| | 129 |
| Cash equivalents | 21 |
| | — |
| | — |
| | 21 |
| Total | $ | 21 |
| | $ | 132 |
| | $ | — |
| | $ | 153 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 13 |
| | $ | — |
| | $ | 13 |
| Foreign currency derivatives | — |
| | 23 |
| | — |
| | 23 |
| Contingent consideration | — |
| | — |
| | 22 |
| | 22 |
| Total | $ | — |
| | $ | 36 |
| | $ | 22 |
| | $ | 58 |
|
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | | Quoted Prices in Active Markets for Identical Assets | | Significant Other Observable Inputs | | Significant Unobservable Inputs | | | As of December 31, 2016: | (Level 1) | | (Level 2) | | (Level 3) | | Total | | (in millions) | Assets: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 21 |
| | $ | — |
| | $ | 21 |
| Interest rate derivatives | — |
| | 1 |
| | — |
| | 1 |
| Cash equivalents | 628 |
| | — |
| | — |
| | 628 |
| Total | $ | 628 |
| | $ | 22 |
| | $ | — |
| | $ | 650 |
| Liabilities: | | | | | | | | Energy-related derivatives | $ | — |
| | $ | 5 |
| | $ | — |
| | $ | 5 |
| Foreign currency derivatives | — |
| | 58 |
| | — |
| | 58 |
| Contingent consideration | — |
| | — |
| | 18 |
| | 18 |
| Total | $ | — |
| | $ | 63 |
| | $ | 18 |
| | $ | 81 |
|
|
Financial instruments not having carrying amount equal to fair value |
As of December 31, 2017 and 2016, other financial instruments for which the carrying amount did not equal fair value were as follows: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt, including securities due within one year: | | | | 2017 | $ | 5,841 |
| | $ | 6,079 |
| 2016 | $ | 5,628 |
| | $ | 5,691 |
|
|
SOUTHERN Co GAS |
|
Fair Value Disclosures [Line Items] |
|
Assets and liabilities measured at fair value on a recurring basis |
As of December 31, 2017, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | As of December 31, 2017: | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | | Net Asset Value as a Practical Expedient (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 331 |
| | $ | 223 |
| | $ | — |
| | $ | — |
| | $ | 554 |
| Liabilities: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 479 |
| | $ | 181 |
| | $ | — |
| | $ | — |
| | $ | 660 |
|
| | (a) | Energy-related derivatives excludes $11 million associated with premiums and certain weather derivatives accounted for based on intrinsic value rather than fair value. |
| | (b) | Energy-related derivatives excludes cash collateral of $193 million. |
As of December 31, 2016, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: | | | | | | | | | | | | | | | | | | | | | | Fair Value Measurements Using | | | As of December 31, 2016: | Quoted Prices in Active Markets for Identical Assets (Level 1) | | Significant Other Observable Inputs (Level 2) | | Significant Unobservable Inputs (Level 3) | | Net Asset Value as a Practical Expedient (NAV) | | Total | | (in millions) | Assets: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 338 |
| | $ | 239 |
| | $ | — |
| | $ | — |
| | $ | 577 |
| Liabilities: | | | | | | | | | | Energy-related derivatives(a)(b) | $ | 345 |
| | $ | 224 |
| | $ | — |
| | $ | — |
| | $ | 569 |
|
| | (a) | Energy-related derivatives excludes $4 million associated with certain weather derivatives accounted for based on intrinsic value rather than fair value. |
| | (b) | Energy-related derivatives excludes cash collateral of $62 million. |
|
Financial instruments not having carrying amount equal to fair value |
The following table presents the carrying amount and fair value of the Company's long-term debt as of December 31: | | | | | | | | | | Carrying Amount | | Fair Value | | (in millions) | Long-term debt, including securities due within one year: | | | | 2017 | $ | 6,048 |
| | $ | 6,471 |
| 2016 | $ | 5,281 |
| | $ | 5,491 |
|
|