Summary of Significant Accounting Policies Inventory (Tables)

12 Months Ended

Dec. 31, 2023

Balance Sheet Related Disclosure - Inventory [Abstract]

Public Utilities, Inventory

Inventory — Inventory is recorded at the lower of average cost or net realizable value and consisted of the following:

(Millions of Dollars)	Dec. 31, 2023		Dec. 31, 2022
Inventories
Materials and supplies	$	91	$	80
Fuel	83		68
Natural gas	84		171
Total inventories	$	258	$	319