Employee Benefit Plans (Other Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined contribution plan contribution rates as percentage of employee earnings	6.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100.00%
Compensation expense related to the ESOP	$ 61	$ 56	$ 52
Deductible dividends on PPG shares held by the ESOP	11	11	10
Recognized expense for defined contribution pension plans	90	92	88
Expense (income) of the deferred compensation plan	23	23	20
Increase (Decrease) in fair value of investments	21	24	$ 18
Obligations under the deferred compensation plan	113	105
Investments in marketable securities by the deferred compensation plan	$ 83	$ 70
Minimum
Defined contribution plan contribution rates as percentage of employee earnings	2.00%
Maximum
Defined contribution plan contribution rates as percentage of employee earnings	5.00%