CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 551.7	$ 494.1	$ 463.5
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	566.1	475.6	446.2
Deferred income taxes	23.8	207.8	222.0
Allowance for equity funds used during construction	(56.4)	(29.8)	(18.6)
Provision for bad debts	16.4	14.3	14.1
Net realized and unrealized hedging and derivative transactions	(6.2)	2.4	1.3
Changes in operating assets and liabilities:
Accounts receivable	(42.8)	(2.2)	(14.2)
Accrued unbilled revenues	(17.7)	1.3	(20.9)
Inventories	(20.1)	(9.1)	0.2
Prepayments and other	12.8	0.2	68.7
Accounts payable	68.7	20.4	38.4
Net regulatory assets and liabilities	(14.6)	(22.6)	4.2
Other current liabilities	(12.9)	71.8	1.9
Pension and other employee benefit obligations	(44.2)	(16.5)	(10.6)
Other Operating Activities, Cash Flow Statement	(16.3)	(5.9)	(29.9)
Net cash provided by operating activities	1,008.3	1,201.8	1,166.3
Investing activities
Utility capital/construction expenditures	(1,577.2)	(1,445.9)	(1,095.2)
Proceeds from Insurance Recoveries	0.0	0.0	0.6
Investments in utility money pool arrangement	(634.0)	(954.0)	(444.0)
Repayments from utility money pool arrangement	654.0	934.0	444.0
Other	0.0	(0.7)	(1.5)
Net cash used in investing activities	(1,557.2)	(1,466.6)	(1,096.1)
Financing activities
Proceeds from (repayments of) short-term borrowings, net	307.0	(129.0)	115.0
Borrowings under utility money pool arrangement	780.0	40.0	524.5
Repayments under utility money pool arrangement	(780.0)	(40.0)	(524.5)
Proceeds from issuance of long-term debt	691.1	393.8	244.5
Repayments of long-term debt	(300.0)	0.0	(129.5)
Capital contributions from parent	252.1	335.6	38.8
Dividends paid to parent	(375.3)	(333.9)	(336.6)
Other	(0.1)	(0.1)	0.0
Net cash provided by (used in) financing activities	574.8	266.4	(67.8)
Net change in cash and cash equivalents	25.9	1.6	2.4
Cash and cash equivalents at beginning of period	7.5	5.9
Cash and cash equivalents at end of period	33.4	7.5	5.9
Supplemental disclosure of cash flow information:
Cash paid for interest (net of amounts capitalized)	(187.2)	(175.0)	(171.7)
Cash (paid) received for income taxes, net	(115.8)	(7.7)	22.8
Supplemental disclosure of non-cash investing transactions:
Accrued property, plant and equipment additions	142.1	199.1	81.1
Inventory transfers to plant, property and equipment	37.2	26.6	40.8
Allowance for Funds Used During Construction, Investing Activities	$ 56.4	$ 29.8	$ 18.6