v3.26.3
Future Policy Benefits (Assumption Explanations) (Details) - Other Segments - USD ($)
Sep. 30, 2026
Sep. 30, 2025
Life Insurance Product Line [Member] | Americas [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate $ 15,500,000,000 $ 15,400,000,000
Future Policy Benefits Actual To Expected Variance (3,000,000) (61,000,000)
Impact Of Updating Discount Rate Recognized In OCI (1,500,000) 375,000,000
Changes In Cash Flow Assumptions 4,000,000 29,000,000
Life Insurance Product Line [Member] | CANADA    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 3,600,000,000 3,600,000,000
Future Policy Benefits Actual To Expected Variance (9,000,000) (3,000,000)
Impact Of Updating Discount Rate Recognized In OCI (323,000,000) 152,000,000
Changes In Cash Flow Assumptions 20,000,000 9,000,000
Life Insurance Product Line [Member] | EMEA [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 2,100,000,000 1,900,000,000
Future Policy Benefits Actual To Expected Variance 33,000,000 10,000,000
Impact Of Updating Discount Rate Recognized In OCI 127,000,000 243,000,000
Changes In Cash Flow Assumptions 31,000,000 223,000,000
Life Insurance Product Line [Member] | Asia Pacific [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 5,800,000,000 5,300,000,000
Future Policy Benefits Actual To Expected Variance 11,000,000 (65,000,000)
Impact Of Updating Discount Rate Recognized In OCI (314,000,000) 49,000,000
Changes In Cash Flow Assumptions 15,000,000 2,000,000
Insurance, Other | Americas [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 11,700,000,000 10,000,000,000
Future Policy Benefits Actual To Expected Variance (8,000,000) (3,000,000)
Impact Of Updating Discount Rate Recognized In OCI (811,000,000) (260,000,000)
Changes In Cash Flow Assumptions 13,000,000 0
Insurance, Other | CANADA    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 4,500,000,000 4,600,000,000
Future Policy Benefits Actual To Expected Variance 0 0
Impact Of Updating Discount Rate Recognized In OCI (314,000,000) (135,000,000)
Changes In Cash Flow Assumptions 0 0
Insurance, Other | EMEA [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 11,200,000,000 10,100,000,000
Future Policy Benefits Actual To Expected Variance 19,000,000 19,000,000
Impact Of Updating Discount Rate Recognized In OCI 578,000,000 128,000,000
Changes In Cash Flow Assumptions 0 24,000,000
Insurance, Other | Asia Pacific [Member]    
Liability for Future Policy Benefit, by Product Segment [Line Items]    
Net Liability For Future Policy Benefits At Original Discount Rate 22,100,000,000 15,500,000,000
Future Policy Benefits Actual To Expected Variance 38,000,000 6,000,000
Impact Of Updating Discount Rate Recognized In OCI (975,000,000) (1,500,000,000)
Changes In Cash Flow Assumptions $ 4,000,000 $ 0