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Fair Value Measurements - Changes in balances of Level 3 financial liabilities carried at fair value (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |  |  |  |
Financial liabilities, Beginning Balance |  | $ (1,759) | [1] | $ (1,369) |  | $ (3,861) |
Impact of accounting change |  |  |  |  |  | 2,701 |
Total realized/unrealized gains (losses) included in Net earnings |  | (589) |  | (211) |  | (17) |
Total realized/unrealized gains (losses) included in other comprehensive income (loss) |  | 0 |  | 0 |  | 0 |
Purchases and issuances |  | (300) |  | (277) |  | (257) |
Sales and settlements |  | 106 |  | 98 |  | 65 |
Transfer into Level 3 |  | 0 |  | 0 |  | 0 |
Transfer out of Level 3 |  | 0 |  | 0 |  | 0 |
Sale of subsidiaries |  |  |  |  |  | 0 |
Financial liabilities, Ending Balance |  | (2,542) | [2] | (1,759) | [1] | (1,369) |
Liabilities of MIE |  |  |  |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |  |  |  |
Financial liabilities, Beginning Balance |  |  |  | 0 |  | (2,701) |
Impact of accounting change | [3] |  |  |  |  | 2,701 |
Total realized/unrealized gains (losses) included in Net earnings |  |  |  |  |  | 0 |
Total realized/unrealized gains (losses) included in other comprehensive income (loss) |  |  |  |  |  | 0 |
Purchases and issuances |  |  |  |  |  | 0 |
Sales and settlements |  |  |  |  |  | 0 |
Transfer into Level 3 |  |  |  |  |  | 0 |
Transfer out of Level 3 |  |  |  |  |  | 0 |
Sale of subsidiaries |  |  |  |  |  | 0 |
Financial liabilities, Ending Balance |  |  |  |  |  | 0 |
Embedded derivatives |  |  |  |  |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |  |  |  |
Financial liabilities, Beginning Balance |  | (1,759) |  | (1,369) |  | (1,160) |
Impact of accounting change |  |  |  |  |  | 0 |
Total realized/unrealized gains (losses) included in Net earnings |  | (589) | [4] | (211) | [5] | (17) | [6]
Total realized/unrealized gains (losses) included in other comprehensive income (loss) |  | 0 |  | 0 |  | 0 |
Purchases and issuances |  | (300) |  | (277) |  | (257) |
Sales and settlements |  | 106 |  | 98 |  | 65 |
Transfer into Level 3 |  | 0 |  | 0 |  | 0 |
Transfer out of Level 3 |  | 0 |  | 0 |  | 0 |
Sale of subsidiaries |  |  |  |  |  | 0 |
Financial liabilities, Ending Balance |  | $ (2,542) |  | $ (1,759) |  | $ (1,369) |
[1] | As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
[2] | As previously discussed, these tables exclude the portion of MIE liabilities allocated to Level 3, which are derived from the fair value of the MIE assets.
[3] | The impact of implementing new guidance adopted in 2015, as discussed in Note A — “Accounting Policies — Managed Investment Entities.”
[4] | Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $25 million in 2017.
[5] | Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $17 million in 2016.
[6] | Total realized/unrealized gains (losses) included in net earnings for the embedded derivatives reflects losses related to the unlocking of actuarial assumptions of $28 million in 2015.

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- Definition Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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