STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Total common shareholder's equity	Common stock	Additional paid-in capital	Retained earnings
Balance at Dec. 31, 2017		$ 1,617.3	$ 95.6	$ 996.1	$ 525.6
Equity
Net income	$ 172.8	172.8	0.0	0.0	172.8
Equity contribution from parent	120.0	120.0	0.0	120.0	0.0
Payment of dividends to parent	(140.0)	(140.0)	0.0	0.0	(140.0)
Other		(0.2)	0.0	(0.2)	0.0
Balance at Dec. 31, 2018		1,769.9	95.6	1,115.9	558.4
Equity
Net income	184.7	184.7	0.0	0.0	184.7
Equity contribution from parent	105.0	105.0	0.0	105.0	0.0
Payment of dividends to parent	(120.0)	(120.0)	0.0	0.0	(120.0)
Other		0.2	0.0	0.2	0.0
Balance at Dec. 31, 2019		1,939.8	95.6	1,221.1	623.1
Equity
Net income	221.6	221.6	0.0	0.0	221.6
Equity contribution from parent	215.0	215.0	0.0	215.0	0.0
Payment of dividends to parent	$ (260.0)	(260.0)	0.0	0.0	(260.0)
Other		0.3	0.0	0.3	0.0
Balance at Dec. 31, 2020		$ 2,116.7	$ 95.6	$ 1,436.4	$ 584.7