Debt (Recourse Debt Carrying Amount and Terms) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022
Debt Instrument [Line Items]
Recourse Debt Total	$ 4,464		$ 3,894
Recourse Debt Current	(200)		0
Recourse Debt Non Current	4,264		3,894
Commercial Paper | Corporate Other And Other Eliminations
Debt Instrument [Line Items]
Commercial Paper Maximum Borrowings		$ 750
Commercial Paper Borrowed and Repaid	45,800
Commercial Paper, Average Outstanding	$ 449
Recourse Debt
Debt Instrument [Line Items]
Percentage of capital stock of foreign subsidiaries securing obligations	65.00%
Maximum ratio of debt to cash flow	5.75
Senior Notes [Member] | 900 Million Senior Notes Due 2028 | Corporate Other And Other Eliminations
Debt Instrument [Line Items]
Debt face amount	$ 900
Stated interest rate	5.45%
Senior Notes [Member] | Revolving Credit Facility due 2027 | Corporate and Other
Debt Instrument [Line Items]
Debt face amount	$ 1,500
Senior Notes [Member] | Revolving Credit Facility due 2026 | Corporate and Other
Debt Instrument [Line Items]
Debt face amount				$ 1,250
Senior Notes [Member] | 200 Million Term Loan due September 2024 | Corporate and Other
Debt Instrument [Line Items]
Debt face amount				200
Senior Notes [Member] | 200 Million Term Loan due September 2024 Amount Borrowed | Corporate and Other
Debt Instrument [Line Items]
Debt face amount				$ 200
Revolving Credit Facility [Member] | Recourse Debt | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Revolving Credit Facility due 2027
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
Unamortized Discounts [Member]
Debt Instrument [Line Items]
Recourse Debt Total	$ (36)		(31)
Parent Company [Member]
Debt Instrument [Line Items]
Recourse Debt Total	4,464
Recourse Debt Current	(200)
Parent Company [Member] | Revolving Credit Facility [Member] | Senior Variable Rate Term Loan due 2024 | Recourse Debt
Debt Instrument [Line Items]
Recourse Debt Total	200		200
Parent Company [Member] | Revolving Credit Facility [Member] | Recourse Debt | Revolving Credit Facility due 2027
Debt Instrument [Line Items]
Recourse Debt Total	$ 0		325
Parent Company [Member] | 3.30% Senior Notes Due 2025 | Recourse Debt
Debt Instrument [Line Items]
Interest Rate	3.30%
Recourse Debt Total	$ 900		900
Parent Company [Member] | 1.375% Senior Notes Due 2026 | Recourse Debt
Debt Instrument [Line Items]
Interest Rate	1.375%
Recourse Debt Total	$ 800		800
Parent Company [Member] | 3.95% Senior Notes Due 2030 | Recourse Debt
Debt Instrument [Line Items]
Interest Rate	3.95%
Recourse Debt Total	$ 700		700
Parent Company [Member] | 2.45% Senior Notes Due 2031 | Recourse Debt
Debt Instrument [Line Items]
Interest Rate	2.45%
Recourse Debt Total	$ 1,000		1,000
Parent Company [Member] | Senior Variable Rate Term Loan due 2024 | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Recourse Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
Parent Company [Member] | Unamortized Discounts [Member]
Debt Instrument [Line Items]
Recourse Debt Total	$ (36)		(31)
Parent Company [Member] | 5.45% Senior Notes Due 2028 | Recourse Debt
Debt Instrument [Line Items]
Interest Rate	5.45%
Recourse Debt Total	$ 900		$ 0