Capitalization (Narrative) (Details) - USD ($) $ in Thousands				1 Months Ended	9 Months Ended	12 Months Ended
	Aug. 15, 2024	Aug. 13, 2024	Jan. 08, 2024	Jan. 31, 2023	Sep. 30, 2024	Dec. 31, 2023	Jun. 12, 2024	Aug. 31, 2023
At Market Sales Agreements 2024 [Member]
Debt Instrument [Line Items]
Common stock shares future issuance and sale at aggregate offering price		$ 1,000,000
Sale of stock, shares					823,595
Common stock issued					$ 32,000
Stock remaining available for sale, amount					$ 968,000
At Market Sales Agreements 2022 [Member]
Debt Instrument [Line Items]
Sale of stock, shares					0	10,260,833
Common stock issued						$ 386,023
First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Face Amount								$ 225,000
First Mortgage Bonds Due In 2053 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate								5.48%
Face Amount								$ 175,000
First Mortgage Bonds Due In 2061 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate								5.56%
Face Amount								$ 50,000
Notes At 5.375%, Due 2034 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate			5.375%		5.375%
Maturity date					2034
Debt issuance expense			$ 4,610
Maturity Year			2034
Unsecured notes payable			$ 500,000		$ 500,000
Notes At 4.80%, Due 2027 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate	4.80%
Debt issuance expense	$ 3,015
Maturity Year	2027
Unsecured notes payable	$ 500,000
Aqua Pennsylvania, Inc [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate				5.60%
Face Amount				$ 75,000
Debt term					364 days
Maturity Year				2043
Aqua Pennsylvania, Inc [Member] | 364-Day Revolving Credit Agreements [Member]
Debt Instrument [Line Items]
Face Amount							$ 100,000
Peoples Natural Gas Companies [Member] | 364-Day Revolving Credit Agreements [Member]
Debt Instrument [Line Items]
Face Amount							$ 300,000