Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating Activities
Net income	$ 745.5	$ 460.4
Reconciliation to cash provided by operating activities
Depreciation and amortization	581.5	390.9
Deferred income taxes and investment tax credits, net	439.5	220.1
Contributions and payments related to pension and OPEB plans	(23.5)	(109.3)
Equity income in transmission affiliate, net of distributions	(35.8)	(17.8)
Change in -
Accounts receivable and unbilled revenues	185.2	269.5
Materials, supplies, and inventories	33.8	(101.4)
Other current assets	88.5	75.6
Accounts payable	(94.7)	(55.9)
Other current liabilities	(92.9)	97.9
Other, net	(105.2)	(155.6)
Net cash provided by operating activities	1,721.9	1,074.4
Investing Activities
Capital expenditures	(1,000.1)	(791.8)
Business acquisition, net of cash acquired of $156.3	0.0	(1,329.9)
Capital contributions to transmission affiliate	(27.1)	(5.6)
Proceeds from the sale of assets and businesses	161.2	26.7
Withdrawal of restricted cash from Rabbi trust for qualifying payments	23.8	0.7
Other, net	0.6	4.0
Net cash used in investing activities	(841.6)	(2,095.9)
Financing Activities
Exercise of stock options	40.4	26.4
Purchase of common stock	(105.6)	(66.1)
Dividends paid on common stock	(468.6)	(310.9)
Issuance of long-term debt	200.0	1,650.0
Retirement of long-term debt	(253.5)	(27.1)
Change in short-term debt	(305.6)	(270.5)
Other, net	(12.2)	(20.0)
Net cash (used in) provided by financing activities	(905.1)	981.8
Net change in cash and cash equivalents	(24.8)	(39.7)
Cash and cash equivalents at beginning of period	49.8	61.9
Cash and cash equivalents at end of period	$ 25.0	$ 22.2