Short-Term Borrowings, Long-Term Debt and Available Credit Facilities Repurchase Facility and Revolving Credit Facilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Feb. 20, 2024 USD ($)	Dec. 31, 2023 USD ($)	May 01, 2023 USD ($)	Feb. 01, 2023 USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 6,000
Line of Credit Facility, Maximum Borrowing Capacity	6,000
Proceeds from debt	1,675	$ 626
Repayments of Long-term Debt	190	56
Foreign Currency Loans
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	24
Revolving Credit Facilities due 2022
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,000
Debt Instrument, Term	3 years
Revolving Credit Facilities due 2024 [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Term	5 years
Revolving Credit Facilities due 2025 [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 2,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,000
Revolving Credit Facilities due 2025 [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Adjusted Term SOFR	0.10%
Revolving Credit Facilities due 2027
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 3,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 3,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Ratio of Indebtedness to Net Capital	0.60
364-day Revolving Credit Facilities due 2023
Line of Credit Facility [Line Items]
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000		$ 1,000		$ 1,000	$ 1,000
Debt Instrument, Term	364 days
Ratio of Indebtedness to Net Capital	0.60
364-day Revolving Credit Facilities due 2023 | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Adjusted Term SOFR	0.10%
Securities Sold under Agreements to Repurchase [Member] | 364-day Revolving Credit Facilities due 2023
Line of Credit Facility [Line Items]
Short-term borrowings	$ 0	$ 1,000		$ 0