Noncontrolling Interest - Net Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Consolidated Net Income	$ 2,529	$ 2,435	$ 2,031
Net income (loss) attributable to noncontrolling interests	32	12	(2)
Southern Power [Member]
Noncontrolling Interest [Line Items]
Consolidated Net Income	374	229	175
Net income (loss) attributable to noncontrolling interests	32	12	(2)
Net income attributable to redeemable noncontrolling interest	4	2	4
Net income attributable to Southern Power Company	338	215	172
Noncontrolling Interests [Member] | Southern Power [Member]
Noncontrolling Interest [Line Items]
Net income (loss) attributable to noncontrolling interests	$ 32	$ 12	$ (1)