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Restructuring Costs (Restructuring Activities) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2023
Restructuring Reserve [Roll Forward] |  |  |  |  |
Liability at beginning of period |  |  | $ 130 | $ 146 | $ 146
Restructuring charges | $ 54 | $ 52 | 140 | 170 | 301
Cash payments |  |  | (195) |  | (271)
Non-cash charges |  |  | (9) |  | (46)
Liability at end of period | 66 |  | 66 |  | 130
Severance |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Liability at beginning of period |  |  | 89 | 88 | 88
Restructuring charges |  |  | 63 |  | 148
Cash payments |  |  | (123) |  | (147)
Non-cash charges |  |  | 0 |  | 0
Liability at end of period | 29 |  | 29 |  | 89
Real Estate Related Costs |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Liability at beginning of period |  |  | 39 | 56 | 56
Restructuring charges |  |  | 41 |  | 96
Cash payments |  |  | (34) |  | (69)
Non-cash charges |  |  | (9) |  | (44)
Liability at end of period | 37 |  | 37 |  | 39
Information Technology |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Liability at beginning of period |  |  | 0 | 0 | 0
Restructuring charges |  |  | 19 |  | 15
Cash payments |  |  | (19) |  | (13)
Non-cash charges |  |  | 0 |  | (2)
Liability at end of period | 0 |  | 0 |  | 0
Consulting and Other Outside Services |  |  |  |  |
Restructuring Reserve [Roll Forward] |  |  |  |  |
Liability at beginning of period |  |  | 2 | $ 2 | 2
Restructuring charges |  |  | 17 |  | 42
Cash payments |  |  | (19) |  | (42)
Non-cash charges |  |  | 0 |  | 0
Liability at end of period | $ 0 |  | $ 0 |  | $ 2

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- Definition Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482017/420-10-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 17 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-17 + Details
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- Definition Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 28 -Subparagraph (b) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-28 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4.b.1) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482047/420-10-45-3 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.P.3) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479823/420-10-S99-1 + Details
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- Definition Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4.b.2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482017/420-10-50-1 + Details
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
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- Definition Amount of decrease in the reserve for full or partial settlement through consideration other than cash. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4.b.2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482017/420-10-50-1 + Details
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