Income Taxes

6 Months Ended

Jun. 30, 2019

Income Tax Disclosure [Abstract]

Income Taxes

INCOME TAXES

The following table presents a reconciliation of the federal statutory corporate income tax rate to the effective income tax rate for the three and six months ended June 30, 2019 and 2018:

	Ameren			Ameren Missouri			Ameren Illinois
Three Months	2019	2018		2019	2018		2019	2018
Federal statutory corporate income tax rate:	21%	21%		21%	21%		21%	21%
Increases (decreases) from:
Amortization of excess deferred taxes	(9)	(1)	(a)	(12)	—	(a)	(4)	(5)
Depreciation differences	—	—		—	—		(1)	(1)
Amortization of deferred investment tax credit	—	—		(1)	(1)		—	—
State tax	6	5		4	4		7	8
Tax credits	—	(1)		—	—		—	—
Effective income tax rate	18%	24%		12%	24%		23%	23%
Six Months
Federal statutory corporate income tax rate:	21%	21%		21%	21%		21%	21%
Increases (decreases) from:
Amortization of excess deferred taxes	(8)	(2)	(a)	(12)	—	(a)	(4)	(4)
Depreciation differences	—	—		1	—		—	—
Amortization of deferred investment tax credit	—	(1)		(1)	(1)		—	—
State tax	6	6		4	4		7	7
Stock-based compensation	(3)	(1)		—	—		—	—
Other	(1)	—		(1)	—		—	—
Effective income tax rate	15%	23%		12%	24%		24%	24%

(a)

Based on an order by the MoPSC in July 2018, Ameren Missouri began amortizing excess deferred taxes in August 2018.