Regulatory Matters - Retail Rate Case Filing (Details) - ACC - ARIZONA PUBLIC SERVICE COMPANY								12 Months Ended
	Oct. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)	Aug. 13, 2018 USD ($)	Feb. 13, 2018	Jan. 08, 2018 USD ($)	Jan. 03, 2018 Customer	Mar. 27, 2017 USD ($) $ / kWh	Dec. 31, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory impact, operating results								$ (10,000,000)
Requested rate increase for tax act	$ 184,000,000		$ (86,500,000)		$ (119,100,000)
Retail Rate Case Filing with Arizona Corporation Commission
Public Utilities, General Disclosures [Line Items]
Base rate decrease, elimination of tax expense adjustment mechanism	$ 115,000,000
Approximate percentage of increase in average customer bill	5.60%						3.28%
Approximate percentage of increase in average residential customer bill	5.40%			4.54%			4.54%
Rate matter, cost base rate		$ 8,870,000,000
Rate matter, funding limited income crisis bill program	$ 1,250,000
Settlement agreement, net retail base rate increase							$ 94,600,000
Settlement agreement, non-fuel, non-depreciation, base rate increase							87,200,000
Fuel-related base rate decrease							53,600,000
Base rate increase, changes in depreciation schedules							$ 61,000,000.0
Authorized return on common equity (as a percent)							10.00%
Percentage of debt in capital structure							44.20%
Percentage of common equity in capital structure							55.80%
Resource comparison proxy for exported energy (in dollars per kWh) | $ / kWh							0.129
Number of customers which signed complaint | Customer						25
AZ Sun II Program | Retail Rate Case Filing with Arizona Corporation Commission
Public Utilities, General Disclosures [Line Items]
Minimum annual renewable energy standard and tariff							$ 10,000,000
Maximum annual renewable energy standard and tariff							$ 15,000,000
Minimum
Public Utilities, General Disclosures [Line Items]
Regulatory impact, operating results	$ 69,000,000
Minimum | Retail Rate Case Filing with Arizona Corporation Commission
Public Utilities, General Disclosures [Line Items]
Environmental surcharge cap rate (in dollars per kWh) | $ / kWh							0.00016
Maximum | Retail Rate Case Filing with Arizona Corporation Commission
Public Utilities, General Disclosures [Line Items]
Environmental surcharge cap rate (in dollars per kWh) | $ / kWh							0.00050