Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2020

Retirement Benefits [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 June 30,				Six Months Ended June 30,
(in millions)	2020		2019		2020		2019
Service cost	$	8	$	7	$	16	$	15
Other components of net benefit credit:
Interest cost	17		20		35		40
Expected return on plan assets	(42)		(41)		(85)		(83)
Amortization of prior service credit	(5)		(4)		(10)		(9)
Amortization of net loss	13		8		27		17
Total other components of net benefit credit	(17)		(17)		(33)		(35)
Net periodic defined benefit credit	$	(9)	$	(10)	$	(17)	$	(20)

Non-Qualified Defined Benefit Pension Plan	Three Months Ended June 30,				Six Months Ended June 30,
(in millions)	2020		2019		2020		2019
Service cost	$	—	$	1	$	1	$	2
Other components of net benefit cost:
Interest cost	2		2		4		4
Amortization of prior service credit	(2)		(2)		(4)		(4)
Amortization of net loss	2		2		4		4
Total other components of net benefit cost	2		2		4		4
Net periodic defined benefit cost	$	2	$	3	$	5	$	6

Postretirement Benefit Plan	Three Months Ended June 30,				Six Months Ended June 30,
(in millions)	2020		2019		2020		2019
Other components of net benefit credit:
Interest cost	$	—	$	—	$	—	$	1
Expected return on plan assets	(1)		—		(1)		(1)
Net periodic defined benefit credit	$	(1)	$	—	$	(1)	$	—