SHARE-BASED COMPENSATION - SHARE-BASED COMPENSATION EXPENSE/ OPTIONS (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Number of shares available for future grants (in shares)	5,056,550
Number of shares authorized for issuance (in shares)	5,056,550
Share-based compensation expense, before income taxes	$ 61.0	$ 58.0	$ 62.0
Income tax benefit	(17.0)	(16.0)	(17.0)
Share-based Payment Arrangement, Expense, after Tax	44.0	42.0	45.0
Capitalized share-based compensation cost	11.0	9.0	11.0
Excess income tax (benefit) deficiency	$ (3.0)	$ (9.0)	$ (19.0)
Stock option exercise period (in years)	3 years
Weighted-average fair value for options granted (in dollars per share)	$ 21.98	$ 19.07	$ 19.76
Stock price volatility (as a percent)	26.08%	26.57%	18.78%
Expected term (in years)	5 years 4 months 9 days	5 years 4 months 9 days	5 years 4 months 2 days
Risk-free rate of return (as a percent)	1.40%	0.41%	1.68%
Annual dividend yield (as a percent)	3.33%	3.38%	2.60%
Common shares under options
Beginning balance (in shares)	537,344
Options grants in period (in shares)	219,898	222,620	154,860
Exercised (in shares)	(40,630)	(50,671)	(4,400)
Ending balance (in shares)	716,612	537,344
Vested at period end (in shares)	716,612
Exercisable at period end (in shares)	307,563
Weighted- average exercise price
Beginning balance (in dollars per share)	$ 123.45
Granted (in dollars per share)	131.99
Exercised (in dollars per share)	106.76
Ending balance (in dollars per share)	127.02	$ 123.45
Vested at period end, Weighted- average exercise price (in dollars per share)	127.02
Exercisable at period end, Weighted- average exercise price (in dollars per share)	$ 122.09
Outstanding at period end, Weighted- average remaining contractual term	7 years 8 months 19 days
Vested at period end, Weighted- average remaining contractual term	7 years 8 months 19 days
Exercisable at period end, Weighted- average remaining contractual term	6 years 9 months
Outstanding at period end, Aggregate intrinsic value	$ 20.0
Vested at period end, Aggregate intrinsic value	20.0
Exercisable at period end, Aggregate intrinsic value	10.0
Aggregate intrinsic value of options exercised	1.7	$ 1.4	$ 0.4
Weighted-average per share fair value for nonqualified stock options granted (in dollars per share)		$ 123.80	$ 149.12
Cash received from exercise of options	4.0	$ 5.0
San Diego Gas and Electric Company
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	11.0	10.0	$ 11.0
Income tax benefit	(3.0)	(3.0)	(3.0)
Share-based Payment Arrangement, Expense, after Tax	8.0	7.0	8.0
Capitalized share-based compensation cost	6.0	5.0	7.0
Excess income tax (benefit) deficiency	0.0	(1.0)	(3.0)
SoCalGas
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Share-based compensation expense, before income taxes	17.0	14.0	14.0
Income tax benefit	(5.0)	(4.0)	(4.0)
Share-based Payment Arrangement, Expense, after Tax	12.0	10.0	10.0
Capitalized share-based compensation cost	5.0	4.0	4.0
Excess income tax (benefit) deficiency	$ 0.0	$ (1.0)	$ (3.0)
Share-based Payment Arrangement, Option
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Expiration period	10 years
Awards Granted In 2020 and 2019 | Share-based Payment Arrangement, Option
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	3 years
Awarded during or after 2015 | Performance Shares
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	3 years
Award vesting rights maximum additional award	100.00%
Award vesting rights, Increase modifier for top quartile	20.00%
Award vesting rights, decrease modifier for bottom quartile	20.00%
Awarded During Or After 2014
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting rights maximum additional award	100.00%
Awards Granted in 2019 | Restricted Stock Units (RSUs), Service-based
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	3 years
Awards Granted During 2015 Through 2018 | Restricted Stock Units (RSUs), Service-based
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award vesting period	3 years
Minimum | Restricted Stock Units (RSUs), Service-based
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Award requisite service period	3 years