CONDENSED CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Millions, $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Operating revenues	$ 2,108.6	$ 2,377.4
Operating expenses
Cost of sales	734.7	1,009.6
Other operation and maintenance	455.7	550.6
Depreciation and amortization	239.1	226.4
Property and revenue taxes	52.5	48.0
Total operating expenses	1,482.0	1,834.6
Operating income	626.6	542.8
Equity in earnings of transmission affiliates	39.8	36.1
Other income, net	5.6	30.9
Interest expense	129.4	124.4
Other expense	(84.0)	(57.4)
Income before income taxes	542.6	485.4
Income tax expense	90.0	65.0
Net income	452.6	420.4
Preferred stock dividends of subsidiary	0.3	0.3
Net loss attributed to noncontrolling interests	0.2	0.0
Net income attributed to common shareholders	$ 452.5	$ 420.1
Earnings per share
Basic (in dollars per share)	$ 1.43	$ 1.33
Diluted (in dollars per share)	$ 1.43	$ 1.33
Weighted average common shares outstanding
Basic (in shares)	315.4	315.5
Diluted (in shares)	316.7	316.7

The aggregate costs related to goods produced and sold and services rendered by an entity during the reporting period. This excludes costs incurred during the reporting period related to financial services rendered and other revenue generating activities.

Name:	us-gaap_CostOfGoodsAndServicesSold
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Total costs of sales and operating expenses for the period.