Acquisitions and Dispositions of Businesses - Narrative (Details) - USD ($) shares in Millions, $ in Millions				3 Months Ended	6 Months Ended	12 Months Ended
	Oct. 30, 2025	Jan. 01, 2025	Apr. 25, 2024	Jun. 30, 2025	Jun. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Business Combination [Line Items]
Goodwill, measurement period adjustment						$ 21
Gain from disposals of business						1,201	$ 337	$ 4
Disposed of by Sale | NFP Acquisition
Business Combination [Line Items]
Purchase price	$ 2,300
Disposal group, not discontinued operation, gain on disposal	$ 1,200
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (expense)
Intangible assets	$ 760
Goodwill	$ 398
Gain from disposals of business						$ 1,199
Griffiths & Armour
Business Combination [Line Items]
Percentage of capital acquired		100.00%
Aggregate consideration transferred		$ 426
2024 Acquisition
Business Combination [Line Items]
Weighted average useful life						14 years
Acquisition related costs						$ 8
Revenue						$ 101
2024 Acquisition | Contract-Based Intangible Assets
Business Combination [Line Items]
Weighted average useful life						14 years
2024 Acquisition | Tradenames
Business Combination [Line Items]
Weighted average useful life						6 years
2024 Acquisition | Technology And Other Assets
Business Combination [Line Items]
Weighted average useful life						4 years
NFP Acquisition
Business Combination [Line Items]
Percentage of capital acquired			100.00%
Aggregate consideration transferred			$ 9,100		$ 9,129
Cash			$ 3,200		$ 3,247
Number of shares issued for acquisition (up to)			19
Equity interest issued or issuable, value			$ 5,900
Adjustments for cash and certain assumed liabilities			$ 3,900
Increase of intangible assets				$ 125
Decrease of deferred tax liabilities				110
Decrease of other noncurrent assets				61
Decrease of other current assets				28
Goodwill, measurement period adjustment				$ 115