CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,175.5		$ 2,211.7		$ 0.0
Revenues from Alternative Revenue Programs	56.1		58.6		0.0
OPERATING REVENUES
Total operating revenues	2,231.6		2,270.3		2,261.1
Total cost of sales	786.9		892.5		897.6
OPERATING EXPENSES
Other operation and maintenance	491.8		474.6		458.7
Depreciation and amortization	355.0		321.6		283.5
Taxes other than income	93.6		92.0		89.4
Operating expenses	940.4		888.2		831.6
Operating income (loss)	504.3		489.6		531.9
OTHER INCOME (EXPENSE)
Equity in earnings of unconsolidated affiliates	113.9		152.8		131.2
Allowance for equity funds used during construction	4.5		23.8		39.7
Pension and Other Postretirement Benefits Cost (Reversal of Cost)	(9.8)		(10.8)		(21.6)
Other income	21.9		21.7		46.4
Other expense	(23.5)		(23.4)		(14.1)
Net other income	107.0		164.1		181.6
INTEREST EXPENSE
Interest on long-term debt	138.3		157.4		153.6
Allowance for borrowed funds used during construction	(2.8)		(11.7)		(18.0)
Interest on short-term debt and other interest charges	12.4		10.3		8.2
Interest expense	147.9		156.0		143.8
INCOME BEFORE TAXES	463.4		497.7		569.7
INCOME TAX EXPENSE (BENEFIT)	29.8		72.2		(49.3)	[1]
NET INCOME	$ 433.6		$ 425.5		$ 619.0
BASIC AVERAGE COMMON SHARES OUTSTANDING	200.1		199.7		199.7
DILUTED AVERAGE COMMON SHARES OUTSTANDING	200.7		200.5		200.0
BASIC EARNINGS PER AVERAGE COMMON SHARE	$ 2.17	[2]	$ 2.13	[2]	$ 3.10
DILUTED EARNINGS PER AVERAGE COMMON SHARE	2.16	[2]	2.12	[2]	3.10
DIVIDENDS DECLARED PER COMMON SHARE	$ 1.5050		$ 1.3950		$ 1.2700

[1] The Company recorded an income tax benefit of $245.2 million and income tax expense of $10.5 million during the fourth quarter of 2017 due to the Company remeasuring deferred taxes related to the natural gas midstream operations and other operations segments, respectively, as a result of the 2017 Tax Act.

[2] Due to the impact of dilution on the earnings per share calculation, quarterly earnings per share amounts may not add to the total.