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Changes in Accumulated Other Comprehensive Loss (Tables) | 3 Months Ended
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Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items] |
Schedule of changes in accumulated other comprehensive loss including reclassification adjustments, net of tax, by component | The following table shows the changes in Pinnacle West's consolidated accumulated other comprehensive loss, including reclassification adjustments, net of tax, by component for the three months ended March 31, 2018 and 2017 (dollars in thousands):
| Pension and Other Postretirement Benefits |  |  |  | Derivative Instruments |  |  |  | Total
Balance December 31, 2017 | $ | (42,440 | ) |  |  |  | $ | (2,562 | ) |  |  |  | $ | (45,002 | )
OCI (loss) before reclassifications | — |  |  |  |  | (96 | ) |  |  |  | (96 | )
Amounts reclassified from accumulated other comprehensive loss | 900 |  |  | (a) |  | 409 |  |  | (b) |  | 1,309 |
Reclassification of income tax effect related to tax reform | (7,954 | ) |  |  |  | (598 | ) |  |  |  | (8,552 | )
Balance March 31, 2018 | $ | (49,494 | ) |  |  |  | $ | (2,847 | ) |  |  |  | $ | (52,341 | )
Balance December 31, 2016 | $ | (39,070 | ) |  |  |  | $ | (4,752 | ) |  |  |  | $ | (43,822 | )
OCI (loss) before reclassifications | — |  |  |  |  | (770 | ) |  |  |  | (770 | )
Amounts reclassified from accumulated other comprehensive loss | 522 |  |  | (a) |  | 1,207 |  |  | (b) |  | 1,729 |
Balance March 31, 2017 | $ | (38,548 | ) |  |  |  | $ | (4,315 | ) |  |  |  | $ | (42,863 | )
(a) | These amounts primarily represent amortization of actuarial loss, and are included in the computation of net periodic pension cost. See Note 5.
(b) | These amounts represent realized gains and losses and are included in the computation of fuel and purchased power costs and are subject to the PSA. See Note 7.
Arizona Public Service Company |
Accumulated Other Comprehensive Income (Loss) [Line Items] |
Schedule of changes in accumulated other comprehensive loss including reclassification adjustments, net of tax, by component | The following table shows the changes in APS's consolidated accumulated other comprehensive loss, including reclassification adjustments, net of tax, by component for the three months ended March 31, 2018 and 2017 (dollars in thousands):
| Pension and Other Postretirement Benefits |  |  |  | Derivative Instruments |  |  |  | Total
Balance December 31, 2017 | $ | (24,421 | ) |  |  |  | $ | (2,562 | ) |  |  |  | $ | (26,983 | )
OCI (loss) before reclassifications | — |  |  |  |  | (96 | ) |  |  |  | (96 | )
Amounts reclassified from accumulated other comprehensive loss | 857 |  |  | (a) |  | 409 |  |  | (b) |  | 1,266 |
Reclassification of income tax effect related to tax reform | (4,440 | ) |  |  |  | (598 | ) |  |  |  | (5,038 | )
Balance March 31, 2018 | $ | (28,004 | ) |  |  |  | $ | (2,847 | ) |  |  |  | $ | (30,851 | )
Balance December 31, 2016 | $ | (20,671 | ) |  |  |  | $ | (4,752 | ) |  |  |  | $ | (25,423 | )
OCI (loss) before reclassifications | — |  |  |  |  | (770 | ) |  |  |  | (770 | )
Amounts reclassified from accumulated other comprehensive loss | 611 |  |  | (a) |  | 1,207 |  |  | (b) |  | 1,818 |
Balance March 31, 2017 | $ | (20,060 | ) |  |  |  | $ | (4,315 | ) |  |  |  | $ | (24,375 | )
(a) | These amounts primarily represent amortization of actuarial loss and are included in the computation of net periodic pension cost. See Note 5.
(b) | These amounts represent realized gains and losses and are included in the computation of fuel and purchased power costs and are subject to the PSA. See Note 7.

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- Definition Tabular disclosure of the components of accumulated other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
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