Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2019

Retirement Benefits [Abstract]

Schedule of Components of Expense/(Income) Related to Net Benefit Expense

	Pension Benefits Cost
(Dollars in millions)	Second Quarters						Six Months
	2019			2018			2019			2018
Service Cost Included in Labor and Fringe	$	8		$	7		$	16		$	16
Interest Cost	26			23			52			46
Expected Return on Plan Assets	(43		)	(43		)	(86		)	(87		)
Amortization of Net Loss	8			10			15			20
Total Included in Other Income - Net	(9		)	(10		)	(19		)	(21		)
Net Periodic Benefit Credit	$	(1	)	$	(3	)	$	(3	)	$	(5	)
	Other Post-retirement Benefits Cost
(Dollars in millions)	Second Quarters						Six Months
	2019			2018			2019			2018
Service Cost Included in Labor and Fringe	$	1		$	1		$	1		$	1
Interest Cost	1			1			2			3
Amortization of Prior Service Costs	(1		)	—			(3		)	—
Total Included in Other Income - Net	—			1			(1		)	3
Net Periodic Benefit Cost	$	1		$	2		$	—		$	4