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Pension and Other Postretirement Benefit Plans (Details) - USD ($) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
PNM | Pension Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | $ 0 | $ 0 | $ 0 | $ 0
Interest cost | 4,985,000 | 6,294,000 | 14,956,000 | 18,881,000
Expected return on plan assets | (7,363,000) | (8,527,000) | (22,089,000) | (25,577,000)
Amortization of net loss | 4,465,000 | 3,880,000 | 13,395,000 | 11,639,000
Amortization of prior service cost | (138,000) | (241,000) | (415,000) | (724,000)
Net Periodic Benefit Cost (Income) | 1,949,000 | 1,406,000 | 5,847,000 | 4,219,000
Contributions by employer |  |  | 0 | 0
Expected employer contributions, remainder of fiscal year | 0 |  | 0 |
Estimated employer contributions in next fiscal year | 0 |  | 0 |
Expected employer contributions in year 3 | 4,600,000 |  | 4,600,000 |
Expected employer contributions in year 4 | 19,100,000 |  | 19,100,000 |
Expected employer contributions in year 5 | 19,000,000.0 |  | $ 19,000,000.0 |
PNM | Pension Plan | Minimum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 3.40% |
PNM | Pension Plan | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 3.50% |
PNM | OPEB Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 9,000 | 13,000 | $ 29,000 | 39,000
Interest cost | 613,000 | 829,000 | 1,840,000 | 2,487,000
Expected return on plan assets | (1,387,000) | (1,320,000) | (4,161,000) | (3,956,000)
Amortization of net loss | 87,000 | 169,000 | 261,000 | 507,000
Amortization of prior service cost | 0 | (99,000) | 0 | (297,000)
Net Periodic Benefit Cost (Income) | (678,000) | (408,000) | (2,031,000) | (1,220,000)
Contributions by employer | 0 |  | 0 | 0
Disbursements by employer | 1,000,000.0 | 900,000 | 3,100,000 | 2,400,000
Total expected employer disbursements for remainder of fiscal year | 3,700,000 |  | 3,700,000 |
Expected employer disbursements in year 2 through 5 | 13,500,000 |  | 13,500,000 |
PNM | Executive Retirement Program |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 123,000 | 163,000 | 367,000 | 487,000
Expected return on plan assets | 0 | 0 | 0 | 0
Amortization of net loss | 101,000 | 79,000 | 302,000 | 237,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost (Income) | 224,000 | 242,000 | 669,000 | 724,000
Disbursements by employer | 300,000 | 400,000 | 1,100,000 | 1,100,000
Total expected employer disbursements for remainder of fiscal year | 1,500,000 |  | 1,500,000 |
Expected employer disbursements in year 2 through 5 | 5,400,000 |  | 5,400,000 |
TNMP | Pension Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 545,000 | 672,000 | 1,633,000 | 2,015,000
Expected return on plan assets | (821,000) | (967,000) | (2,463,000) | (2,901,000)
Amortization of net loss | 315,000 | 235,000 | 944,000 | 706,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost (Income) | 39,000 | (60,000) | 114,000 | (180,000)
Contributions by employer |  |  | 0 | 0
Expected employer contributions in year 4 | 1,100,000 |  | 1,100,000 |
Expected employer contributions in year 5 | 2,800,000 |  | 2,800,000 |
Estimated employer contributions remainder of fiscal year through year three | 0 |  | $ 0 |
TNMP | Pension Plan | Minimum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 3.40% |
TNMP | Pension Plan | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Assumptions used calculating net periodic benefit cost, discount rate |  |  | 3.50% |
TNMP | OPEB Plan |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 12,000 | 12,000 | $ 35,000 | 39,000
Interest cost | 93,000 | 113,000 | 280,000 | 338,000
Expected return on plan assets | (136,000) | (129,000) | (404,000) | (387,000)
Amortization of net loss | (81,000) | (111,000) | (243,000) | (332,000)
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost (Income) | (112,000) | (115,000) | (332,000) | (342,000)
Estimated employer contributions for remainder of fiscal year through year 5 | 0 |  | 0 |
TNMP | Executive Retirement Program |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Service cost | 0 | 0 | 0 | 0
Interest cost | 6,000 | 7,000 | 17,000 | 24,000
Expected return on plan assets | 0 | 0 | 0 | 0
Amortization of net loss | 6,000 | 4,000 | 18,000 | 11,000
Amortization of prior service cost | 0 | 0 | 0 | 0
Net Periodic Benefit Cost (Income) | 12,000 | 11,000 | 35,000 | 35,000
Total expected employer disbursements for remainder of fiscal year | 100,000 |  | 100,000 |
Expected employer disbursements in year 2 through 5 | 300,000 |  | 300,000 |
TNMP | Executive Retirement Program | Maximum |  |  |  |
Components of Net Periodic Benefit Cost |  |  |  |
Disbursements by employer | $ 0 | $ 0 | $ 0 | $ 0

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