Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities
Net income	$ 1,060.5	$ 1,204.9	$ 940.2
Reconciliation to cash provided by operating activities
Depreciation and amortization	845.8	798.6	762.6
Deferred income taxes and investment tax credits, net	297.3	271.7	493.8
Contributions and payments related to pension and OPEB plans	(77.6)	(120.5)	(28.7)
Equity income in transmission affiliate, net of distributions	(18.6)	(4.8)	(46.6)
Change in -
Accounts receivable and unbilled revenues	23.5	(86.4)	(180.7)
Materials, supplies, and inventories	(8.8)	49.3	100.0
Other current assets	(10.0)	(7.1)	103.2
Accounts payable	110.6	8.5	34.4
Other current liabilities	(67.6)	161.8	(20.8)
Other, net	290.4	(197.4)	(53.6)
Net cash provided by operating activities	2,445.5	2,078.6	2,103.8
Investing Activities
Capital expenditures	(2,115.7)	(1,959.5)	(1,423.7)
Acquisition of Bishop Hill III, net of restricted cash acquired of $4.5 million	(162.9)	0.0	0.0
Acquisition of Forward Wind Energy Center	77.1	0.0	0.0
Acquisition of Coyote Ridge	61.4	0.0	0.0
Acquisition of Bluewater	0.0	(226.0)	0.0
Capital contributions to transmission affiliates	(53.5)	(109.6)	(42.3)
Proceeds from the sale of assets and businesses	12.1	24.0	166.3
Proceeds from the sale of investments held in rabbi trust	118.6	8.7	1.7
Purchase of investments held in rabbi trust	(65.0)	(3.7)	(59.2)
Other, net	20.5	12.0	3.0
Net cash used in investing activities	(2,384.4)	(2,254.1)	(1,354.2)
Financing Activities
Exercise of stock options	29.1	30.8	41.6
Purchase of common stock	(72.4)	(71.3)	(108.0)
Dividends paid on common stock	(697.3)	(656.5)	(624.9)
Issuance of long-term debt	1,740.0	435.0	400.0
Retirement of long-term debt	(953.3)	(154.5)	(306.0)
Change in short-term debt	(4.5)	584.4	(234.8)
Other, net	(15.2)	(6.5)	(13.6)
Net cash provided by (used in) financing activities	26.4	161.4	(845.7)
Net change in cash, cash equivalents, and restricted cash	87.5	(14.1)	(96.1)
Cash, cash equivalents, and restricted cash at beginning of year	58.6	72.7	168.8
Cash, cash equivalents, and restricted cash at end of year	$ 146.1	$ 58.6	$ 72.7