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Stock-based Compensation and Outstanding Awards - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	May 22, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Company common stock were authorized for grant		16,000,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Date		May 31, 2024
Stock-based compensation expense		$ 13	$ 15	$ 11
Shares available for grant		0
Tax effected benefit for share-based compensation arrangements		$ 2	2	2
Share-based compensation arrangement by share-based payment award, options, contractual term		2 years 3 months 18 days
Aggregate intrinsic value, Exercised or settled		$ 3		1
Exercise of stock options		$ 5	2	$ 2
DNOW Inc. Long Term Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period		10 years
2024 Omnibus Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for grant	1,973,000
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value, Exercised or settled			$ 1
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards, vested, number of years		3 years
Share-based compensation arrangement by share-based payment award, options, contractual term		7 years
Exercise of stock options		$ 6
Restricted Stock [Member] \| Cliff Vests After Year One [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards, vested, number of years		1 year
Restricted Stock [Member] \| Cliff Vests After Year Three [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards, vested, number of years		3 years
Restricted Stock and Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation costs		$ 14
Expected to be recognized over a weighted average period		1 year 3 months 18 days
Weighted average grant date fair value, Granted		$ 13.6	$ 12.56	$ 9.89
Fair value of shares vested		$ 5	$ 3	$ 2
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant date fair value, Granted		$ 14.17
Performance-base restricted stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards, vested, number of years		3 years
Unrecognized compensation costs		$ 5
Expected to be recognized over a weighted average period		1 year 1 month 6 days
Weighted average grant date fair value, Granted		$ 14.17	$ 15.52	$ 11.08
Performance-based awards granted, percentage, minimum threshold met		0.00%
Performance-based awards granted, percentage, maximum threshold met		200.00%
Vest-date fair value vested during period		$ 7	$ 1
Performance-base restricted stock [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest-date fair value vested during period				$ 1
TSR metric [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock awards granted in percent		50.00%
Performance based restricted stock awards goals over performance period		3 years
EBITDA metric [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock awards granted in percent		25.00%
Performance based restricted stock awards goals over performance period		3 years
Return on Capital Employed (ROCE) metric [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance based restricted stock awards granted in percent		25.00%
Performance based restricted stock awards goals over performance period		3 years