Borrowings and Credit Agreements - Short-term Borrowings (Details) - USD ($)					1 Months Ended	12 Months Ended
	Jun. 02, 2023	May 02, 2023	May 01, 2023	Feb. 21, 2023	Feb. 28, 2023	Dec. 31, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Short-term debt						$ 200,000,000	$ 0
Proceeds from debt	$ 4,900,000,000		$ 5,000,000,000	$ 6,000,000,000	$ 6,000,000,000
Federal Home Loan Bank advances maximum amount available						1,000,000,000
Commercial Paper
Short-term Debt [Line Items]
Short-term debt						$ 200,000,000	0
Short-term debt, weighted average interest rate						4.31%
Line of Credit | Back-Up Credit Facilities
Short-term Debt [Line Items]
Short-term debt						$ 0	0
Commitment fee percentage						0.03%
Line of Credit | Revolving Credit Facility, Expiring May 16, 2025
Short-term Debt [Line Items]
Maximum borrowing capacity						$ 2,500,000,000
Debt instrument term						5 years
Line of Credit | Revolving Credit Facility, Expiring May 11, 2026
Short-term Debt [Line Items]
Maximum borrowing capacity						$ 2,500,000,000
Debt instrument term						5 years
Line of Credit | Revolving Credit Facility, Expiring May 16, 2027
Short-term Debt [Line Items]
Maximum borrowing capacity						$ 2,500,000,000
Debt instrument term						5 years
Loans Payable | 364-day Term Loan Agreement
Short-term Debt [Line Items]
Debt instrument term			364 days
Debt face amount			$ 5,000,000,000
Proceeds from debt		$ 5,000,000,000
Debt interest rate		6.20%
Federal Home Loan Bank Advances
Short-term Debt [Line Items]
Short-term debt						$ 0	$ 0