Future Policy Benefits (Assumption Explanations) (Details) - Other Segments - USD ($)	Jun. 30, 2025	Jun. 30, 2024
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	$ 14,800,000,000	$ 11,900,000,000
Future Policy Benefits Actual To Expected Variance	(68,000,000)	(103,000,000)
Impact Of Updating Discount Rate Recognized In OCI	(72,000,000)	863,000,000
Changes In Cash Flow Assumptions	0	0
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	3,500,000,000
Future Policy Benefits Actual To Expected Variance	(5,000,000)	(6,000,000)
Impact Of Updating Discount Rate Recognized In OCI	(98,000,000)	243,000,000
Changes In Cash Flow Assumptions	0	0
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	1,700,000,000	1,400,000,000
Future Policy Benefits Actual To Expected Variance	4,000,000	5,000,000
Impact Of Updating Discount Rate Recognized In OCI	83,000,000	66,000,000
Changes In Cash Flow Assumptions	0	0
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	5,200,000,000	4,700,000,000
Future Policy Benefits Actual To Expected Variance	24,000,000	(29,000,000)
Impact Of Updating Discount Rate Recognized In OCI	(122,000,000)	167,000,000
Changes In Cash Flow Assumptions	0	0
Insurance, Other | Americas [Member]
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net Liability For Future Policy Benefits At Original Discount Rate	10,100,000,000	7,600,000,000
Future Policy Benefits Actual To Expected Variance	(3,000,000)	(3,000,000)
Impact Of Updating Discount Rate Recognized In OCI	(100,000,000)	(194,000,000)
Changes In Cash Flow Assumptions	0	0
Insurance, Other | CANADA
Liability for Future Policy Benefit, by Product Segment [Line Items]
Net Liability For Future Policy Benefits At Original Discount Rate	4,600,000,000	4,100,000,000
Future Policy Benefits Actual To Expected Variance	0	0
Impact Of Updating Discount Rate Recognized In OCI	(122,000,000)	(77,000,000)
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	9,100,000,000	6,700,000,000
Future Policy Benefits Actual To Expected Variance	6,000,000	4,000,000,000
Impact Of Updating Discount Rate Recognized In OCI	51,000,000	289,000,000
Changes In Cash Flow Assumptions	0	0
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	15,800,000,000	10,700,000,000
Future Policy Benefits Actual To Expected Variance	5,000,000	1,000,000
Impact Of Updating Discount Rate Recognized In OCI	(995,000,000)	(107,000,000)
Changes In Cash Flow Assumptions	$ 0	$ 0