Consolidated Statement of Cash Flows - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net income attributable to the controlling and noncontrolling interests	$ 1,074	$ 1,269	$ 1,358
Income from discontinued operations, net of tax	3	0	18
Income from continuing operations	1,071	1,269	1,340
Adjustments to reconcile net income to cash from operations:
Depreciation and amortization	509	511	497
Pension expense	43	54	43
Pension curtailment charges	13	0	0
Gain (Loss) on Extinguishment of Debt	7	0	0
Business restructuring	174	176	66
Impairment charges	93	0	0
Environmental remediation charges and other costs, net	26	61	77
Stock-based compensation expense	44	39	37
Gain on sale of land	0	0	(26)
Equity affiliate loss/(income), net of dividends	10	4	(1)
Deferred income taxes	(47)	(5)	45
Cash contributions to pension plans	(17)	(13)	(99)
Cash used for restructuring actions	(126)	(58)	(66)
Change in certain asset and liability accounts (net of acquisitions):
Receivables	187	121	(69)
Inventories	111	145	(109)
Other current assets	49	(95)	5
Accounts payable and accrued liabilities	127	(63)	(76)
Noncurrent assets and liabilities, net	(25)	(13)	(207)
Taxes and interest payable	(108)	(32)	50
Other	(12)	(17)	(20)
Cash from operating activities - continuing operations	2,129	2,084	1,487
Cash from/(used for) operating activities - discontinued operations	1	(4)	(20)
Cash from operating activities	2,130	2,080	1,467
Investing activities
Capital expenditures	(304)	(413)	(411)
Business acquisitions, net of cash balances acquired	(1,169)	(643)	(378)
Proceeds from sale of land	0	0	27
Payments for the settlement of cross currency swap contracts	(5)	(8)	(28)
Proceeds from the settlement of cross currency swap contracts	22	28	23
Other	9	27	3
Cash used for investing activities	(1,447)	(1,009)	(764)
Financing activities
Net change in borrowings with maturities of three months or less	(6)	6	(1)
Proceeds on commercial paper and short-term debt, net of payments	1,647	100	(2)
Repayment of Term Loan	(1,100)	0	0
Proceeds from revolving credit facility	800	0	0
Repayment of revolving credit facility	(800)	0	0
Proceeds from the issuance of debt, net of discounts and fees	415	595	992
Repayment of long-term debt	(504)	(637)	(6)
Repayment of acquired debt	(13)	(23)	0
Payments related to tax withholding on stock-based compensation awards	(17)	(20)	(15)
Purchase of treasury stock	0	(325)	(1,721)
Issuance of treasury stock	54	61	15
Dividends paid on PPG common stock	(496)	(468)	(453)
Purchase of noncontrolling interest	0	(39)	0
Other	(39)	(8)	(14)
Cash used for financing activities	(59)	(758)	(1,205)
Effect of currency exchange rate changes on cash and cash equivalents	6	1	(32)
Cash reclassified to assets held for sale	(20)	0	0
Net increase/(decrease) in cash and cash equivalents	610	314	(534)
Cash and cash equivalents, beginning of year	1,216	902	1,436
Cash and cash equivalents, end of year	1,826	1,216	902
Supplemental disclosures of cash flow information:
Interest paid, net of amount capitalized	153	127	108
Taxes paid, net of refunds	$ 367	$ 348	$ 380
Reissuance of common stock for business acquisition	0	164	0