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Statement of Financial Position (Parentheticals) $ in Millions | Jun. 30, 2021 USD ($) shares | Dec. 31, 2020 USD ($) shares
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Statement of Financial Position [Abstract] |  |
Available for sale, at amortized cost | $ 88,265 | $ 85,188
Debt Securities, Available-for-sale, Allowance for Credit Loss | 11 | 20
Held to maturity, Fair Value | 11,343 | 12,510
Debt Securities, Held-to-maturity, Allowance for Credit Loss | 37 | 44
short-term investments amortized cost | 4,471 | 4,349
Premium Receivable, Allowance for Credit Loss | 42 | 44
Reinsurance Recoverable, Allowance for Credit Loss | $ 322 | $ 314
Common Shares, shares issued | shares | 477,605,264 | 477,605,264
Common Shares, shares outstanding | shares | 438,717,213 | 450,732,625
Common Shares in treasury, shares | shares | 38,888,051 | 26,872,639

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