Accumulated Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2019

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

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

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

	Pension and Retiree Health and Welfare Benefit Items			Equity Method Investments			Total
Balance as of December 31, 2016	$	122		$	(3	)	$	119
Other comprehensive income (loss), net before reclassifications	114			—			114
Amounts reclassified from AOCI:
Amortization of prior service creditsa	(2		)	—			(2		)
Tax expense (benefit)	—			—			—
Balance as of December 31, 2017	$	234		$	(3	)	$	231
Other comprehensive income (loss), net before reclassifications	(126		)	1			(125		)
Amounts reclassified from AOCI:
Reclassification due to ASU 2016-01 adoption	—			(1		)	(1		)
Reclassification due to ASU 2018-02 adoption	26			—			26
Amortization of actuarial lossesa	1			—			1
Amortization of prior service creditsa	(3		)	—			(3		)
Tax expense (benefit)	1			—			1
Balance as of December 31, 2018	$	133		$	(3	)	$	130
Other comprehensive income (loss), net before reclassifications	16			(1		)	15
Amounts reclassified from AOCI:
Amortization of prior service creditsa	(4		)	—			(4		)
Settlement lossa	5			—			5
Tax expense (benefit)	(1		)	—			(1		)
Balance as of December 31, 2019	$	149		$	(4	)	$	145

^a This accumulated other comprehensive income component is included in the computation of net periodic pension cost (see Note 13 for additional details).