v3.26.3
Accumulated Other Comprehensive Loss
 9 Months Ended
Sep. 30, 2026
Equity [Abstract]  
Accumulated Other Comprehensive Loss Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive loss by component for the nine months ended September 30, 2026 and 2025 were as follows:
Pension and Other Post-Retirement Benefits Liability, Net of TaxCumulative Foreign Currency
Exchange, Net of Tax
Available-for-sale Securities, Net of Tax
Total
Balances at December 31, 2025$44 $(125)$1 $(80)
Net other comprehensive loss attributable to Westlake Corporation
— (18)(1)(19)
Balances at March 31, 202644 (143)— (99)
Net other comprehensive loss attributable to Westlake Corporation— (17)— (17)
Balance at June 30, 202644 (160)— (116)
Net other comprehensive income (loss) attributable to Westlake Corporation
1 3 (2)2 
Balances at September 30, 2026$45 $(157)$(2)$(114)
Balances at December 31, 2024$54 $(198)$— $(144)
Net other comprehensive income attributable to Westlake Corporation— 14 — 14 
Balances at March 31, 202554 (184)— (130)
Net other comprehensive income attributable to Westlake Corporation1 65 — 66 
Balance at June 30, 2025
55 (119)— (64)
Net other comprehensive income (loss) attributable to Westlake Corporation— (14)1 (13)
Balances at September 30, 2025$55 $(133)$1 $(77)