Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2019

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Components of Net Periodic Benefit Cost

The components of net periodic benefit cost (credit) for the Corporation's qualified pension plan, non-qualified pension plan and postretirement benefit plan are as follows.

Qualified Defined Benefit Pension Plan	Three Months Ended September 30,						Nine Months Ended September 30,
(in millions)	2019			2018			2019			2018
Service cost	$	8		$	7		$	23		$	22
Other components of net benefit credit:
Interest cost	20			19			60			56
Expected return on plan assets	(41		)	(41		)	(124		)	(123		)
Amortization of prior service credit	(5		)	(5		)	(14		)	(14		)
Amortization of net loss	8			13			25			38
Total other components of net benefit credit	(18		)	(14		)	(53		)	(43		)
Net periodic defined benefit credit	$	(10	)	$	(7	)	$	(30	)	$	(21	)

Non-Qualified Defined Benefit Pension Plan	Three Months Ended September 30,						Nine Months Ended September 30,
(in millions)	2019			2018			2019			2018
Service cost	$	—		$	—		$	2		$	1
Other components of net benefit cost:
Interest cost	3			2			7			6
Amortization of prior service credit	(2		)	(1		)	(6		)	(6		)
Amortization of net loss	1			2			5			7
Total other components of net benefit cost	2			3			6			7
Net periodic defined benefit cost	$	2		$	3		$	8		$	8

Postretirement Benefit Plan	Three Months Ended September 30,					Nine Months Ended September 30,
(in millions)	2019			2018		2019			2018
Other components of net benefit credit:
Interest cost	$	—		$	—	$	1		$	1
Expected return on plan assets	(1		)	—		(2		)	(2		)
Net periodic defined benefit credit	$	(1	)	$	—	$	(1	)	$	(1	)