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Deferred Policy Acquisition Costs - Progression of deferred policy acquisition costs (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward] |  |  |
Deferred policy acquisition costs and present value of future profits, beginning balance | $ 1,037 | $ 1,682 | $ 1,216
Deferred policy acquisition costs and present value of future profits, additions | 703 | 952 | 940
Deferred policy acquisition costs and present value of future profits, periodic amortization | (757) | (860) | (908)
Deferred policy acquisition costs and present value of future profits, annuity unlocking | (114) | (77) | 29
Deferred policy acquisition costs and present value of future profits, change included in realized gains | (41) | 9 | 15
Deferred policy acquisition costs and present value of future profits, foreign currency translation | 0 | 0 | (2)
Deferred policy acquisition costs and present value of future profits, other | (10) |  |
Deferred policy acquisition costs and present value of future profits, change in unrealized | (272) | (669) | 392
Deferred policy acquisition costs and present value of future profits, ending balance | 546 | 1,037 | 1,682
Property and casualty insurance |  |  |
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward] |  |  |
Deferred policy acquisition costs, beginning balance | 322 | 299 | 270
Deferred policy acquisition costs, additions | 547 | 744 | 675
Deferred policy acquisition costs, periodic amortization | (615) | (721) | (644)
Deferred policy acquisition costs, foreign currency translation | 0 | 0 | (2)
Deferred policy acquisition costs, ending balance | 244 | 322 | 299
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward] |  |  |
Deferred policy acquisition costs and present value of future profits, other | (10) |  |
Annuity and Run-off |  |  |
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward] |  |  |
Deferred policy acquisition costs, beginning balance | 1,303 | 1,285 | 1,217
Deferred policy acquisition costs, additions | 154 | 206 | 263
Deferred policy acquisition costs, periodic amortization | (127) | (120) | (238)
Deferred policy acquisition costs, annuity unlocking | (118) | (76) | 29
Deferred policy acquisition costs, change included in realized gains | (42) | 8 | 14
Deferred policy acquisition costs, ending balance | 1,170 | 1,303 | 1,285
Movement in Deferred Sales Inducements [Roll Forward] |  |  |
Deferred sales inducements, beginning balance | 75 | 86 | 102
Deferred sales inducements, additions | 2 | 2 | 2
Deferred sales inducements, periodic amortization | (9) | (13) | (19)
Deferred sales inducements, annuity unlocking | 4 | (1) | 0
Deferred sales inducements, change included in realized gains | 1 | 1 | 1
Deferred sales inducements, ending balance | 73 | 75 | 86
Movement in Present Value of Future Insurance Profits [Roll Forward] |  |  |
Present value of future profits, beginning balance | 36 | 42 | 49
Present value of future profits, periodic amortization | (6) | (6) | (7)
Present value of future profits, annuity unlocking | 0 | 0 | 0
Present value of future profits, ending balance | 30 | 36 | 42
Movement in Unrealized Gains (Losses) Related to Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward] |  |  |
Unrealized investment gains (losses), beginning balance | (699) | (30) | (422)
Unrealized investment gains (losses), change in unrealized | (272) | (669) | 392
Unrealized investment gains (losses), ending balance | (971) | (699) | (30)
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward] |  |  |
Deferred policy acquisition costs and present value of future profits, beginning balance | 715 | 1,383 | 946
Deferred policy acquisition costs and present value of future profits, additions | 156 | 208 | 265
Deferred policy acquisition costs and present value of future profits, periodic amortization | (142) | (139) | (264)
Deferred policy acquisition costs and present value of future profits, annuity unlocking | (114) | (77) | 29
Deferred policy acquisition costs and present value of future profits, change included in realized gains | (41) | 9 | 15
Deferred policy acquisition costs and present value of future profits, change in unrealized | (272) | (669) | 392
Deferred policy acquisition costs and present value of future profits, ending balance | 302 | 715 | 1,383
Excluding Unrealized Gains | Annuity and Run-off |  |  |
Movement Analysis of Deferred Policy Acquisition Costs and Present Value of Future Profits [Roll Forward] |  |  |
Deferred policy acquisition costs and present value of future profits, beginning balance | 1,414 | 1,413 | 1,368
Deferred policy acquisition costs and present value of future profits, change in unrealized | 0 | 0 | 0
Deferred policy acquisition costs and present value of future profits, ending balance | $ 1,273 | $ 1,414 | $ 1,413

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