Exhibit 12.1

Statement of Computation of Ratio of Earnings to Fixed Charges

The following table sets forth our ratios of earnings to fixed charges for the periods indicated.

	Year ended December 31												Nine months ended September 30
(in millions, except ratios)	2011			2012		2013		2014		2015			2016
Fixed charges:
Interest expense		161			172		186		179		208			339
Allowance for borrowed funds used during construction		11			13		4		5		4			7
Amortization of debt issue costs and discount or premium relating to indebtedness		3			4		3		3		3			6
Preferred stock dividend requirements of subsidiaries		13			13		14		14		16			6
Interest portion of rental expense		1			1		1		1		1			3
Total fixed charges		189			201		208		201		232			361
Earnings available for fixed charges:
Earnings from continuing operations before income taxes		236			233		299		566		545			179
Dividend income of equity investees, net of equity pick up		(3	)		15		14		5		(34	)		(49	)
Add: Fixed charges		189			201		208		201		232			361
Less: Allowance for borrowed funds used during construction		11			13		4		5		4			7
Less: Preferred stock dividend requirements of subsidiaries		13			13		14		14		16			6
Total earnings available for fixed charges		398			425		503		754		723			478
Ratio of earnings to fixed charges		2.1x			2.1x		2.4x		3.7x		3.1x			1.3x