Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net income	$ 940.2	$ 640.3	$ 589.5
Reconciliation to cash provided by operating activities
Depreciation and amortization	762.6	583.5	417.0
Deferred income taxes and investment tax credits, net	493.8	418.7	328.1
Contributions and payments related to pension and OPEB plans	(28.7)	(121.0)	(13.9)
Equity income in transmission affiliate, net of distributions	(46.6)	(11.0)	(8.5)
Change in -
Accounts receivable and unbilled revenues	(180.7)	84.0	80.7
Materials, supplies, and inventories	100.0	(69.4)	(71.2)
Other current assets	103.1	(27.2)	(13.9)
Accounts payable	34.4	(9.3)	23.7
Other current liabilities	(20.8)	14.1	(45.3)
Other, net	(53.8)	(209.1)	(87.3)
Net cash provided by operating activities	2,103.5	1,293.6	1,198.9
Investing Activities
Capital expenditures	(1,423.7)	(1,266.2)	(761.2)
Business acquisition, net of cash acquired	0.0	(1,329.9)	0.0
Cash acquired from business acquisition	156.3
Capital contributions to transmission affiliate	(42.3)	(8.7)	(13.1)
Proceeds from the sale of assets and businesses	166.3	28.9	13.9
Withdrawal of restricted cash from Rabbi Trust for qualifying payments	26.6	1.4	0.0
Other, net	3.0	57.0	3.6
Net cash used in investing activities	(1,270.1)	(2,517.5)	(756.8)
Financing Activities
Exercise of stock options	41.6	30.1	50.3
Purchase of common stock	(108.0)	(74.7)	(123.2)
Dividends paid on common stock	(624.9)	(455.4)	(352.0)
Redemption of WPS preferred stock	0.0	(52.7)	0.0
Issuance of long-term debt	400.0	2,150.0	250.0
Retirement of long-term debt	(306.0)	(529.6)	(324.3)
Change in short-term debt	(234.8)	163.0	80.2
Other, net	(13.6)	(18.9)	12.8
Net cash (used in) provided by financing activities	(845.7)	1,211.8	(406.2)
Net change in cash and cash equivalents	(12.3)	(12.1)	35.9
Cash and cash equivalents at beginning of year	49.8	61.9	26.0
Cash and cash equivalents at end of year	$ 37.5	$ 49.8	$ 61.9