XML 116 R86.htm IDEA: XBRL DOCUMENT v3.20.4
Pension and Other Postretirement Benefits - Components of Net Periodic Benefit Cost (Income) Recognized (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Public Service Company of New Mexico | Pension Plan      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost $ 0 $ 0 $ 0
Interest cost 19,941 25,175 24,270
Expected return on plan assets (29,453) (34,103) (34,686)
Amortization of net (gain) loss 17,860 15,518 16,348
Amortization of prior service cost (554) (965) (965)
Net periodic benefit cost 7,794 5,625 4,967
Public Service Company of New Mexico | Other Postretirement Benefits      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 38 53 83
Interest cost 2,453 3,316 3,439
Expected return on plan assets (5,548) (5,278) (5,414)
Amortization of net (gain) loss 348 675 2,354
Amortization of prior service cost 0 (397) (1,664)
Net periodic benefit cost (2,709) (1,631) (1,202)
Public Service Company of New Mexico | Executive Retirement Program      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 0 0 0
Interest cost 491 651 622
Amortization of net (gain) loss 403 318 359
Amortization of prior service cost 0 0 0
Net periodic benefit cost 894 969 981
Texas-New Mexico Power Company | Pension Plan      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 0 0 0
Interest cost 2,177 2,686 2,625
Expected return on plan assets (3,284) (3,868) (3,963)
Amortization of net (gain) loss 1,258 941 1,088
Amortization of prior service cost 0 0 0
Net periodic benefit cost 151 (241) (250)
Texas-New Mexico Power Company | Other Postretirement Benefits      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 46 50 134
Interest cost 373 451 477
Expected return on plan assets (538) (517) (542)
Amortization of net (gain) loss (323) (444) (227)
Amortization of prior service cost 0 0 0
Net periodic benefit cost (442) (460) (158)
Texas-New Mexico Power Company | Executive Retirement Program      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]      
Service cost 0 0 0
Interest cost 22 30 29
Amortization of net (gain) loss 24 15 15
Amortization of prior service cost 0 0 0
Net periodic benefit cost $ 46 $ 45 $ 44