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Investments (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Nuclear decommissioning trust fund assets |  |  |
Fair Value | $ 871,000 | $ 779,586 |
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds |  |  |
Realized gains | 21,813 | 11,213 | $ 5,189
Realized losses | (13,146) | (10,106) | (6,225)
Proceeds from the sale of securities | 542,246 | 633,410 | 478,813
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Total | 871,000 | 779,586 |
Fixed income securities |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 478,294 |  |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Less than one year | 25,123 |  |
1 year - 5 years | 102,783 |  |
5 years - 10 years | 137,854 |  |
Greater than 10 years | 212,534 |  |
Total | 478,294 |  |
Nuclear Decommissioning Trusts |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 446,277 |  |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Less than one year | 24,668 |  |
1 year - 5 years | 100,289 |  |
5 years - 10 years | 129,239 |  |
Greater than 10 years | 192,081 |  |
Total | 446,277 |  |
Escrow Accounts |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 32,017 |  |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Less than one year | 455 |  |
1 year - 5 years | 2,494 |  |
5 years - 10 years | 8,615 |  |
Greater than 10 years | 20,453 |  |
Total | 32,017 |  |
ARIZONA PUBLIC SERVICE COMPANY |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 871,000 | 779,586 |
Total Unrealized Gains | 260,160 | 197,911 |
Total Unrealized Losses | (2,996) | (4,962) |
Net receivables for securities purchases | 109 | 795 |
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds |  |  |
Proceeds from the sale of securities | 542,246 | 633,410 | $ 478,813
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Total | 871,000 | 779,586 |
ARIZONA PUBLIC SERVICE COMPANY | Equity securities |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 417,390 | 353,261 |
Total Unrealized Gains | 248,623 | 188,091 |
Total Unrealized Losses | 0 | 0 |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Total | 417,390 | 353,261 |
ARIZONA PUBLIC SERVICE COMPANY | Fixed income securities |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 446,277 | 425,530 |
Total Unrealized Gains | 11,537 | 9,820 |
Total Unrealized Losses | (2,996) | (4,962) |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Total | 446,277 | 425,530 |
ARIZONA PUBLIC SERVICE COMPANY | Cash and cash equivalents |  |  |
Nuclear decommissioning trust fund assets |  |  |
Fair Value | 7,224 | 0 |
Total Unrealized Gains | 0 | 0 |
Total Unrealized Losses | 0 | 0 |
Fair value of fixed income securities, summarized by contractual maturities |  |  |
Total | $ 7,224 | $ 0 |

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