v3.26.3
Shareholders' equity AOCI (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Dec. 31, 2024
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other comprehensive income (loss), before income tax $ (3,874) $ 1,286 $ (4,686) $ 3,960        
Other Comprehensive Income (Loss), Tax (357) 40 (472) 116        
Other Comprehensive Income (Loss), Net of Tax (3,517) 1,246 (4,214) 3,844        
Total shareholders' equity 78,512 77,811 78,512 77,811   $ 79,779    
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity (7,757) (1,940) (7,757) (1,940) $ (3,282) (1,997) $ (2,772) $ (4,552)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Including Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), before Reclassifications, before Tax (4,941) 837 (6,604) 2,598        
Net Realized Gains (Losses) Reclassified from AOCI (105) (31) (299) (157)        
Other comprehensive income (loss), before income tax (4,836) 868 (6,305) 2,755        
Other Comprehensive Income (Loss), Tax (370) 52 (559) 163        
Other Comprehensive Income (Loss), Net of Tax (4,466) 816 (5,746) 2,592        
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax 9 (16) 14 (20)        
AOCI, Liability for Future Policy Benefit, Parent                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity 107 (462) 107 (462) (164) (344) (746) (539)
AOCI, Liability for Future Policy Benefit, Including Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other comprehensive income (loss), before income tax 300 305 541 53        
Other Comprehensive Income (Loss), Tax 51 (26) 120 (47)        
Other Comprehensive Income (Loss), Net of Tax 249 331 421 100        
AOCI, Liability for Future Policy Benefit, Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax (22) 47 (30) 23        
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Parent                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity (12) (19) (12) (19) (12) (23) (12) (16)
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Including Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other comprehensive income (loss), before income tax 0 (9) 13 (4)        
Other Comprehensive Income (Loss), Tax 0 (2) 2 (1)        
Other Comprehensive Income (Loss), Net of Tax 0 (7) 11 (3)        
AOCI, Market Risk Benefit, Instrument-Specific Credit Risk, Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax 0 0 0 0        
Cumulative Foreign Currency Translation Adjustment [Member]                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity (2,376) (2,857) (2,376) (2,857) (3,015) (3,135) (2,919) (4,025)
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), before Reclassifications, before Tax 666 136 1,056 1,306        
Net Realized Gains (Losses) Reclassified from AOCI 11 8 31 23        
Other comprehensive income (loss), before income tax 655 128 1,025 1,283        
Other Comprehensive Income (Loss), Tax (40) 17 (44) 26        
Other Comprehensive Income (Loss), Net of Tax 695 111 1,069 1,257        
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax 56 49 310 89        
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity (18) (43) (18) (43) (27) (58) (40) 50
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), before Reclassifications, before Tax (9) (17) (36) 98        
Net Realized Gains (Losses) Reclassified from AOCI (21) (14) (87) 215        
Other comprehensive income (loss), before income tax 12 (3) 51 (117)        
Other Comprehensive Income (Loss), Tax 3 0 11 (24)        
Other Comprehensive Income (Loss), Net of Tax 9 (3) 40 (93)        
Accumulated Gain (Loss), Net, Cash Flow Hedge, Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax 0 0 0 0        
Postretirement Benefit Liability Adjustment [Member]                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Total shareholders' equity 573 429 573 429 577 582 431 438
Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other comprehensive income (loss), before income tax (5) (3) (11) (10)        
Other Comprehensive Income (Loss), Tax (1) (1) (2) (1)        
Other Comprehensive Income (Loss), Net of Tax (4) (2) (9) (9)        
Accumulated Defined Benefit Plans Adjustment Attributable to Noncontrolling Interest                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax 0 0 0 0        
Accumulated Other Comprehensive Income (Loss) [Member]                
AOCI Attributable to Parent, Net of Tax [Roll Forward]                
Other Comprehensive Income (Loss), Net of Tax (3,560) 1,166 (4,508) 3,752        
Total shareholders' equity $ (9,483) $ (4,892) $ (9,483) $ (4,892) $ (5,923) $ (4,975) $ (6,058) $ (8,644)