Retirement Plans and Other Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Pinnacle West | Pension Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Net periodic benefit cost charged to expense	$ 7	$ 8	$ 15	$ 19
Pension Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost - benefits earned during the period	13	13	29	28
Interest cost on benefit obligation	31	30	62	61
Expected return on plan assets	(33)	(31)	(67)	(62)
Amortization of prior service cost			1	1
Amortization of net actuarial loss	7	4	13	10
Net periodic benefit cost	18	16	38	38
Contributions
Expected contribution to benefit plans in the current fiscal year	0		0
Expected contributions for next fiscal period	68		68
Pinnacle West | Other Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Net periodic benefit cost charged to expense	4	3	8	8
Other Benefits
Net periodic benefit costs and the portion of these costs charged to expense
Service cost - benefits earned during the period	5	5	11	10
Interest cost on benefit obligation	12	10	23	21
Expected return on plan assets	(11)	(10)	(21)	(20)
Amortization of transition obligation		(1)
Amortization of net actuarial loss	4	2	8	5
Net periodic benefit cost	10	6	21	16
Contributions
Expected contribution to benefit plans in the current fiscal year	20		20
Expected contributions for next fiscal period	$ 20		$ 20
ARIZONA PUBLIC SERVICE COMPANY
Contributions
APS's share of contributions to the plans (as a percent)	99.00%		99.00%