Income Taxes (Tables)

3 Months Ended

Mar. 31, 2017

Income Tax Disclosure [Abstract]

Change in Unrecognized Tax Benefits

Changes during the three months ended March 31, 2017 for unrecognized tax benefits were as follows:

	Mississippi Power		Southern Power		Southern Company
	(in millions)
Unrecognized tax benefits as of December 31, 2016	$	465	$	17	$	484
Tax positions from current periods	3		1		9
Tax positions from prior periods	—		—		7
Balance as of March 31, 2017	$	468	$	18	$	500

Impact on Effective Tax Rate, If Recognized

The impact on the effective tax rate, if recognized, is as follows:

	As of March 31, 2017						As of December 31, 2016
	Mississippi Power		Southern Power		Southern Company		Southern Company
	(in millions)
Tax positions impacting the effective tax rate	$	4	$	18	$	36	$	20
Tax positions not impacting the effective tax rate	464		—		464		464
Balance of unrecognized tax benefits	$	468	$	18	$	500	$	484