Accumulated Other Comprehensive Income

9 Months Ended

Sep. 30, 2020

Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]

Other comprehensive income refers to revenues, expenses, gains, and losses that under generally accepted accounting principles are included in accumulated other comprehensive income, a component of equity within the Consolidated Balance Sheets, rather than net income on the Consolidated Statements of Income. Under existing accounting standards, other comprehensive income may include, among other things, unrecognized gains and losses and prior service credit related to pension and other postretirement benefit plans.

The following table provides the components of accumulated other comprehensive income (loss) (AOCI) by component (in millions):


	Pension and Retiree Health and Welfare Benefit Items		Equity Method Investments		Accumulated Other Comprehensive Income (Loss)
Balance as of December 31, 2018	$	133	$	(3)	$	130
Other comprehensive income (loss), net before reclassifications	66		(1)		65
Amounts reclassified from AOCI:
Amortization of net gaina	(1)		—		(1)
Amortization of prior service creditsa	(3)		—		(3)
Tax expense (benefit)	1		—		1
Balance as of September 30, 2019	$	196	$	(4)	$	192


Balance as of December 31, 2019	$	149	$	(4)	$	145
Other comprehensive income (loss), net before reclassifications	—		1		1
Amounts reclassified from AOCI:
Amortization of net gaina	1		—		1


Balance as of September 30, 2020	$	150	$	(3)	$	147

a This accumulated other comprehensive income component is included in the computation of net periodic pension cost (see Note 6 for additional details).