Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Comprehensive income (loss):
Net income (loss)	$ 193	$ 2,509	$ (350)
Cash flow hedging activities:
Net unrealized gain (loss) from derivative instruments, net of taxes of $1, $2, and ($1) in 2018, 2017, and 2016, respectively	(7)	(9)	4
Reclassifications into earnings of net derivative instruments (gain) loss, net of taxes of ($1), ($1), and $1 in 2018, 2017, and 2016, respectively	8	6	(2)
Foreign currency translation activities:
Foreign currency translation adjustments, net of taxes of ($37) in 2016	0	1	50
Reclassification into earnings upon sale of foreign entities, net of taxes of ($36) in 2016	0	0	119
Pension and other postretirement benefits:
Amortization of prior service cost (credit) included in net periodic benefit cost (credit), net of taxes of $2 and $2 in 2017, and 2016, respectively	0	(3)	(4)
Net actuarial gain (loss) arising during the year, net of taxes of $3, ($15), and $8 in 2018, 2017 and 2016, respectively	(6)	44	(15)
Amortization of actuarial (gain) loss and net actuarial loss from settlements included in net periodic benefit cost (credit), net of taxes of ($11), ($37), and ($12) in 2018, 2017, and 2016, respectively (Note 10)	35	61	20
Other comprehensive income (loss)	30	100	172
Comprehensive income (loss)	223	2,609	(178)
Less: Comprehensive income (loss) attributable to noncontrolling interests	346	334	143
Comprehensive Income (loss) attributable to The Williams Companies, Inc.	$ (123)	$ 2,275	$ (321)