Employee Pension and Other Postretirement Benefits (Tables)

6 Months Ended

Jun. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Components of Net Periodic Benefit Cost

The following table summarizes the components of net periodic benefit cost for the three and six months ended June 30, 2016 and 2015.

	Pension Benefits						Other Postretirement Benefits						Superannuation, SERP and ESBP
	For the Three Months Ended   June 30,						For the Three Months Ended   June 30,						For the Three Months Ended   June 30,
(Dollars in millions)	2016			2015			2016			2015			2016		2015
Components of net periodic benefit cost:
Service cost	$	22		$	23		$	2		$	2		$	—	$	1
Interest cost	26			28			2			2			1		1
Expected return on plan assets	(58		)	(54		)	(4		)	(4		)	—		—
Amortization of prior service credit	(5		)	(5		)	(2		)	(2		)	—		—
Recognized net actuarial loss	19			26			3			1			—		—
Total net periodic benefit cost	$	4		$	18		$	1		$	(1	)	$	1	$	2

	Pension Benefits						Other Postretirement Benefits						Superannuation, SERP and ESBP
	For the Six Months Ended June 30,						For the Six Months Ended June 30,						For the Six Months Ended June 30,
(Dollars in millions)	2016			2015			2016			2015			2016		2015
Components of net periodic benefit cost:
Service cost	$	45		$	48		$	4		$	4		$	1	$	1
Interest cost	52			55			5			5			1		1
Expected return on plan assets	(118		)	(108		)	(9		)	(9		)	—		—
Amortization of prior service credit	(9		)	(9		)	(4		)	(4		)	—		—
Recognized net actuarial loss	38			53			5			2			1		1
Total net periodic benefit cost	$	8		$	39		$	1		$	(2	)	$	3	$	3