Employee Benefits (Tables)

9 Months Ended

Sep. 30, 2021

Retirement Benefits [Abstract]

Schedule of Components of Net Periodic Pension Benefit (Income) Expense and Post-retirement Benefit Expense

Net periodic pension benefit expense (income) for the Lumen Combined Pension Plan ("Combined Pension Plan" or the "Plan") includes the following components:

	Combined Pension Plan
	Three Months Ended September 30,			Nine Months Ended September 30,
	2021		2020	2021	2020
	(Dollars in millions)
Service cost	$	14	15	42	44
Interest cost	49		81	148	243
Expected return on plan assets	(138)		(147)	(414)	(445)
Settlements	57		—	57	—
Recognition of prior service credit	(2)		(3)	(7)	(7)
Recognition of actuarial loss	49		50	147	152
Net periodic pension benefit expense (income)	$	29	(4)	(27)	(13)

Net periodic benefit expense for our post-retirement benefit plans includes the following components:

	Post-Retirement Benefit Plans
	Three Months Ended September 30,			Nine Months Ended September 30,
	2021		2020	2021	2020
	(Dollars in millions)
Service cost	$	4	4	11	11
Interest cost	12		17	35	57
Recognition of prior service cost	3		4	11	12
Recognition of actuarial loss	2		—	4	—
Curtailment loss	—		7	—	7
Net periodic post-retirement benefit expense	$	21	32	61	87