v3.26.3
Shareholders' Equity - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period $ 20,032 $ 18,389 $ 19,641 $ 17,937
Other comprehensive income (loss) before reclassifications, after tax (1,024) 361 (1,161) 714
Reclassification of (income) losses from accumulated other comprehensive loss, after tax (3) 10 17 57
Other comprehensive income (loss) (1,027) 371 (1,144) 771
Amounts attributable to noncontrolling interests 85 (30) 94 (64)
Other       (1)
Balance at end of period 19,143 19,223 19,143 19,223
Net Unrealized Gains (Losses) on Investments with an Allowance for Credit Losses        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax (3) (1) (18) (11)
Reclassification of (income) losses from accumulated other comprehensive loss, after tax 3 4 10 12
Other comprehensive income (loss) 0 3 (8) 1
Amounts attributable to noncontrolling interests 1 1
Other      
Other comprehensive income (loss) before reclassifications, tax 0 1 4 4
Reclassification of losses from accumulated other comprehensive loss, tax 0 (2) (2) (4)
Net Unrealized Gains (Losses) on Other Investments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax (1,836) 552 (2,081) 872
Reclassification of (income) losses from accumulated other comprehensive loss, after tax (6) 4 4 40
Other comprehensive income (loss) (1,842) 556 (2,077) 912
Amounts attributable to noncontrolling interests 151 (45) 170 (75)
Other       (1)
Other comprehensive income (loss) before reclassifications, tax 492 (148) 559 (233)
Reclassification of losses from accumulated other comprehensive loss, tax 2 0 (1) (11)
Cumulative impact of changes in discount rates used to measure long duration contracts        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax 818 (150) 998 (267)
Reclassification of (income) losses from accumulated other comprehensive loss, after tax
Other comprehensive income (loss) 818 (150) 998 (267)
Amounts attributable to noncontrolling interests (67) 12 (82) 22
Other      
Other comprehensive income (loss) before reclassifications, tax (217) 40 (265) 71
Reclassification of losses from accumulated other comprehensive loss, tax 0 0 0 0
Unrealized Gains (Losses) on Cash Flow Hedges        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax 3 6 (6)
Reclassification of (income) losses from accumulated other comprehensive loss, after tax
Other comprehensive income (loss) 3 0 6 (6)
Amounts attributable to noncontrolling interests
Other      
Other comprehensive income (loss) before reclassifications, tax (1) 2 (3) 5
Reclassification of losses from accumulated other comprehensive loss, tax 0 0 0 0
Pension and Postretirement Benefits        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax 1 (1) (2) (2)
Reclassification of (income) losses from accumulated other comprehensive loss, after tax 2 3 5
Other comprehensive income (loss) 1 1 1 3
Amounts attributable to noncontrolling interests
Other      
Other comprehensive income (loss) before reclassifications, tax 0 0 1 0
Reclassification of losses from accumulated other comprehensive loss, tax 0 0 (1) (1)
Foreign Currency Translation        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Other comprehensive income (loss) before reclassifications, after tax (7) (39) (64) 128
Reclassification of (income) losses from accumulated other comprehensive loss, after tax
Other comprehensive income (loss) (7) (39) (64) 128
Amounts attributable to noncontrolling interests 3 5 (11)
Other      
Other comprehensive income (loss) before reclassifications, tax 0 0 0 0
Reclassification of losses from accumulated other comprehensive loss, tax 0 0 0 0
Accumulated Other Comprehensive Income (Loss)        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period (1,175) (1,502) (1,067) (1,867)
Other comprehensive income (loss) (942) 341 (1,050) 707
Balance at end of period (2,117) (1,161) (2,117) (1,161)
Net Unrealized Gains (Losses) on Investments with an Allowance for Credit Losses        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period (23) (15) (15) (13)
Balance at end of period (22) (12) (22) (12)
Net Unrealized Gains (Losses) on Other Investments        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period (1,123) (1,395) (907) (1,720)
Balance at end of period (2,814) (884) (2,814) (884)
Cumulative impact of changes in discount rates used to measure long duration contracts        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period 341 217 176 324
Balance at end of period 1,092 79 1,092 79
Unrealized Gains (Losses) on Cash Flow Hedges        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period 5 3 2 9
Balance at end of period 8 3 8 3
Pension and Postretirement Benefits        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period (212) (222) (212) (224)
Balance at end of period (211) (221) (211) (221)
Foreign Currency Translation        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period (163) (90) (111) (243)
Balance at end of period $ (170) $ (126) $ (170) $ (126)