EBP Net Periodic Benefit Cost & OCI (Details 2) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pension Benefits [Member]
Components of net periodic benefit cost (credit):
Service cost		$ 25	$ 23	$ 28
Interest cost		47	46	31
Expected return on plan assets		(60)	(57)	(44)
Amortization of net actuarial loss (gain)		0	5	12
Net actuarial loss from settlements		1	0	3
Reclassification to regulatory liability		0	0	0
Net periodic benefit cost (credit) (1)	[1]	13	17	30
Items Recognized in Other Comprehensive Income (Loss)
Net actuarial gain (loss) arising during the year		93	(5)	(14)
Amortization of net actuarial loss (gain)		0	5	12
Net actuarial loss from settlements		1	0	3
Total recognized in Other comprehensive income (loss)		94	0	1
Other Postretirement Benefits [Member]
Components of net periodic benefit cost (credit):
Service cost		1	1	1
Interest cost		7	7	6
Expected return on plan assets		(11)	(10)	(10)
Amortization of net actuarial loss (gain)		(5)	(3)	0
Net actuarial loss from settlements		0	0	0
Reclassification to regulatory liability		0	0	1
Net periodic benefit cost (credit) (1)	[1]	(8)	(5)	(2)
Items Recognized in Other Comprehensive Income (Loss)
Net actuarial gain (loss) arising during the year		3	3	14
Amortization of net actuarial loss (gain)		(2)	(2)	0
Net actuarial loss from settlements		0	0	0
Total recognized in Other comprehensive income (loss)		$ 1	$ 1	$ 14

[1] Components other than Service cost are included in Other income (expense) – net below Operating income (loss) in Williams’ Consolidated Statement of Income.