Regulatory Matters - Cost Recovery Mechanisms (Details)																							3 Months Ended	12 Months Ended
	Apr. 19, 2024	Nov. 30, 2023 USD ($) $ / kWh	Oct. 25, 2023 USD ($)	Oct. 11, 2023	Jul. 31, 2023 USD ($)	Jul. 01, 2023 USD ($) $ / KWH_Kilowatt_hour	Jun. 01, 2023 USD ($)	May 01, 2023 $ / kWh	Mar. 10, 2023 USD ($)	Feb. 23, 2023 $ / kWh	Feb. 01, 2023 USD ($) $ / kWh	Sep. 23, 2022 MW	Jul. 12, 2022 USD ($) $ / kWh	Jun. 01, 2022 USD ($)	Feb. 15, 2022 USD ($)	Feb. 01, 2022 $ / kWh	Oct. 01, 2021 $ / kWh	Jun. 01, 2021 USD ($)	Feb. 15, 2021 USD ($)	Feb. 01, 2020 $ / kWh	Oct. 31, 2019 $ / KWH_Kilowatt_hour	Sep. 01, 2017	Mar. 31, 2024 USD ($)	Dec. 31, 2023 storage	Dec. 31, 2022 storage	Dec. 31, 2021 storage	Dec. 31, 2020 program MW	Oct. 27, 2023 USD ($)	Jun. 30, 2023 USD ($)	May 31, 2023 USD ($)	Nov. 30, 2022 USD ($)	Jul. 01, 2022 USD ($)	Apr. 18, 2022 USD ($)	Dec. 17, 2021 USD ($)	Dec. 09, 2021 USD ($)	Jul. 01, 2021 USD ($)
APS
Public Utilities, General Disclosures [Line Items]
Number of energy storage PPA | storage																								9	1	4
Number of energy storage PPA, terminated | storage																										1
Annual amount of approved equity infusions																							$ 150,000,000
Increased in equity contributions																												$ 500,000,000
APS | Damage from Fire, Explosion or Other Hazard
Public Utilities, General Disclosures [Line Items]
Past due balance threshold qualifying for payment extension																																	$ 75
APS | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public utilities, request to permanently modify permitted yearly equity infusions	2.50%
ACC | APS
Public Utilities, General Disclosures [Line Items]
Program term																											18 years
Number of programs | program																											2
Solar capacity (in MW) | MW																											80
RES | ACC | APS
Public Utilities, General Disclosures [Line Items]
Plan term																							5 years
RES 2018 | ACC | APS
Public Utilities, General Disclosures [Line Items]
Amount of proposed budget																													$ 95,100,000			$ 86,200,000			$ 100,500,000	$ 93,100,000
RES 2018 | ACC | APS | Solar Communities
Public Utilities, General Disclosures [Line Items]
Program term													3 years
RES 2018 | ACC | APS | Minimum
Public Utilities, General Disclosures [Line Items]
Authorized spending													$ 20,000,000
RES 2018 | ACC | APS | Maximum
Public Utilities, General Disclosures [Line Items]
Authorized spending													$ 30,000,000
Retail Rate Case Filing with Arizona Corporation Commission | APS | Maximum
Public Utilities, General Disclosures [Line Items]
Fixed cost recoverable per power lost (in dollars per kWh) | $ / KWH_Kilowatt_hour																					2.68
Retail Rate Case Filing with Arizona Corporation Commission | ACC | APS
Public Utilities, General Disclosures [Line Items]
Commercial customers, market pricing, threshold | MW												140
Demand Side Management Adjustor Charge 2022 | ACC | APS
Public Utilities, General Disclosures [Line Items]
Amount of proposed budget																																		$ 78,400,000
Increase in proposed budget																																		$ 14,000,000
2023 Transportation Electrification Plan | ACC | APS
Public Utilities, General Disclosures [Line Items]
Amount of proposed budget																															$ 5,000,000
Demand Side Management Adjustor Charge 2023 | ACC | APS
Public Utilities, General Disclosures [Line Items]
Amount of proposed budget																														$ 88,000,000	$ 88,000,000
Demand Side Management Adjustor Charge 2024 | ACC | APS
Public Utilities, General Disclosures [Line Items]
Amount of proposed budget		$ 91,500,000
Power Supply Adjustor (PSA) | ACC | APS
Public Utilities, General Disclosures [Line Items]
PSA rate (in dollars per kWh) | $ / kWh		0.019074								0.019074	0.006					0.007544
PSA rate for prior year (in dollars per kWh) | $ / kWh		(0.012624)								(0.005527)						0.004842
Forward component of increase in PSA (in dollars per kWh) | $ / kWh		0.013071								0.013071						0.012386
Transition component of PSA rate | $ / kWh		0.011530								0.011530
Depletion period										24 months
Reporting threshold amount of balancing account		$ 100,000,000
Approved PSA rate | $ / kWh		0.011977
Power Supply Adjustor (PSA) | ACC | APS | Cost Recovery Mechanisms
Public Utilities, General Disclosures [Line Items]
Maximum increase decrease in PSA rate | $ / kWh																				0.006
Historical component of increase in PSA (in dollars per kWh) | $ / kWh																0.004
Environmental Improvement Surcharge | FERC | APS
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in annual wholesale transmission rates									$ (10,700,000)		$ 14,700,000
Rate matters, increase (decrease) in cost recovery, excess of annual amount									(7,500,000)		$ 3,300,000
Rate matter, environmental surcharge cap rate amount									$ 4,000,000
Open Access Transmission Tariff | FERC | APS
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in annual wholesale transmission rates							$ 34,700,000							$ (33,000,000)				$ 4,000,000
Rate matters, increase (decrease) in cost recovery, wholesale customer rates							20,700,000							6,400,000				3,200,000
Increase (decrease) in retail customer rates							14,000,000							(26,600,000)				7,200,000
Rate matters, increase (decrease) in retail revenue requirements							$ 10,000,000							$ 2,400,000				$ 28,400,000
Lost Fixed Cost Recovery Mechanisms | APS
Public Utilities, General Disclosures [Line Items]
Percentage of retail revenues																							1.00%
Fixed cost recoverable per power lost (in dollars per kWh) | $ / KWH_Kilowatt_hour																					2.56
Amount of adjustment representing prorated sales losses pending approval					$ 68,700,000										$ 59,100,000
Increase (decrease) in amount of adjustment representing prorated sales losses															$ 32,500,000				$ 11,800,000
Amount of adjustment representing annual recovery					$ 9,600,000
Lost Fixed Cost Recovery Mechanisms | ACC
Public Utilities, General Disclosures [Line Items]
Amount of adjustment approved to transfer			$ 27,100,000
Court Resolution Surcharge | ACC | APS
Public Utilities, General Disclosures [Line Items]
Court resolution surcharge (in dollars per kWh) | $ / KWH_Kilowatt_hour						0.00175
Lost revenue recovery						$ 59,600,000
Navajo Nation Reservation | Coal Community Transition Plan | APS | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Lost revenue recovery collected																							$ 12,700,000
Net Metering | ACC | APS
Public Utilities, General Disclosures [Line Items]
Cost of service, resource comparison proxy method, maximum annual percentage decrease				10.00%				10.00%					10.00%									10.00%
Cost of service for interconnected DG system customers, grandfathered period																						20 years
Cost of service for new customers, guaranteed export price period																						10 years
Second-year export energy price (in dollars per kWh) | $ / kWh													0.0846				0.094
Third-year export energy price (in dollars per kWh) | $ / kWh								0.07619