EBP Asset rollforward and B.S. classification (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
Net regulatory liabilities	$ 139	$ 123
Pension Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	1,167	1,117
Actual return on plan assets	88	120
Employer contributions	4	1
Plan participants’ contributions	0	0
Benefits paid	(73)	(71)
Settlements	(3)	0
Net increase (decrease) in fair value of plan assets	16	50
Fair value of plan assets at end of year	1,183	1,167
Funded status — overfunded (underfunded)	246	161
Amounts recognized in the Consolidated Balance Sheet:
Noncurrent assets	270	187
Current liabilities	(4)	(4)
Noncurrent liabilities	(20)	(22)
Funded status - overfunded (underfunded)	246	161
Accumulated benefit obligation	929	998
Plans with a projected benefit obligation in excess of plan assets:
Projected benefit obligation	23	26
Plans with an accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	22	24
Fair value of plan assets	0	0
Amounts recognized in Accumulated other comprehensive income (loss):
Net actuarial gain (loss)	49	(45)
Other Postretirement Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	262	253
Actual return on plan assets	16	17
Employer contributions	3	3
Plan participants’ contributions	2	2
Benefits paid	(11)	(13)
Settlements	0	0
Net increase (decrease) in fair value of plan assets	10	9
Fair value of plan assets at end of year	272	262
Funded status — overfunded (underfunded)	140	117
Amounts recognized in the Consolidated Balance Sheet:
Noncurrent assets	143	120
Current liabilities	(3)	(3)
Noncurrent liabilities	0	0
Funded status - overfunded (underfunded)	140	117
Amounts recognized in Accumulated other comprehensive income (loss):
Net actuarial gain (loss)	$ 20	$ 19