Consolidated Statement of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Comprehensive income (loss):
Net income (loss)	$ 322	$ 315	$ 757	$ (255)
Cash flow hedging activities:
Net unrealized gain (loss) from derivative instruments, net of taxes of $7 and $9 in 2021 and $— and $— in 2020	(17)	0	(26)	0
Reclassifications into earnings of net derivative instruments (gain) loss, net of taxes of ($2) and ($2) in 2021 and $— and $— in 2020	4	0	6	0
Pension and other postretirement benefits:
Net actuarial gain (loss) arising during the year, net of taxes of $— and $— in 2021 and ($7) and ($3) in 2020	0	23	0	9
Amortization of actuarial (gain) loss and net actuarial loss from settlements included in net periodic benefit cost (credit), net of taxes of ($1) and ($2) in 2021 and ($3) and ($5) in 2020	3	6	6	14
Other comprehensive income (loss)	(10)	29	(14)	23
Comprehensive income (loss)	312	344	743	(232)
Less: Comprehensive income (loss) attributable to noncontrolling interests	18	12	27	(41)
Comprehensive income (loss) attributable to The Williams Companies, Inc.	$ 294	$ 332	$ 716	$ (191)