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Goodwill and Other Intangible Assets - Schedule of other intangible assets by asset class (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items] |  |  |
Gross Carrying Amount | $ 2,786 | $ 3,673 |
Accumulated Amortization and Impairment | 2,146 | 2,890 |
Net Carrying Amount | 640 | 783 |
Amortization and impairment of intangible assets | 246 | 392 | $ 593
Customer-related and contract-based |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Gross Carrying Amount | 2,337 | 2,264 |
Accumulated Amortization and Impairment | 1,775 | 1,600 |
Net Carrying Amount | 562 | 664 |
Trade Names |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Gross Carrying Amount | 14 | 1,029 |
Accumulated Amortization and Impairment | 13 | 956 |
Net Carrying Amount | 1 | 73 |
Impairment of intangible assets | 1,000 |  |
Technology and other |  |  |
Finite-Lived Intangible Assets [Line Items] |  |  |
Gross Carrying Amount | 435 | 380 |
Accumulated Amortization and Impairment | 358 | 334 |
Net Carrying Amount | $ 77 | $ 46 |

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