Benefit Plans - Schedule of Fair Values of Pension Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Free-standing derivatives, liabilities | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value		$ (1)
Free-standing derivatives, liabilities | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value		(5)
Free-standing derivatives, liabilities | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value		0
Pension benefits
Components of net periodic cost
Total plan assets at fair value	$ 2,574	$ 2,732
Total plan assets at fair value, allocation (as a percent)	100.00%	100.00%
Investments measured using the net asset value practical expedient	$ 2,019	$ 1,975
Securities lending obligation (3)	(179)	(296)
Derivatives counterparty and cash collateral netting	8	2
Other net plan assets (4)	18	17
Total reported plan assets	4,440	4,430	$ 6,525
Pension benefits | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	$ 609	$ 779
Total plan assets at fair value, allocation (as a percent)	23.70%	28.50%
Pension benefits | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	$ 1,965	$ 1,953
Total plan assets at fair value, allocation (as a percent)	76.30%	71.50%
Pension benefits | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	$ 0	$ 0
Total plan assets at fair value, allocation (as a percent)	0.00%	0.00%
Total reported plan assets	$ 0	$ 0	2	$ 2
Pension benefits | Equity securities
Components of net periodic cost
Total plan assets at fair value	160	145
Pension benefits | Equity securities | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	132	120
Pension benefits | Equity securities | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	28	25
Pension benefits | Equity securities | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	0
Total reported plan assets	0	0	2	0
Pension benefits | Government bonds
Components of net periodic cost
Total plan assets at fair value	1,330	1,392
Pension benefits | Government bonds | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	323	496
Pension benefits | Government bonds | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	1,007	896
Pension benefits | Government bonds | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Corporate bonds
Components of net periodic cost
Total plan assets at fair value	794	757
Pension benefits | Corporate bonds | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Corporate bonds | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	794	757
Pension benefits | Corporate bonds | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	0
Total reported plan assets			$ 0	$ 2
Pension benefits | Short-term investments
Components of net periodic cost
Total plan assets at fair value	298	442
Pension benefits | Short-term investments | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	154	163
Pension benefits | Short-term investments | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	144	279
Pension benefits | Short-term investments | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Free-standing derivatives, assets
Components of net periodic cost
Total plan assets at fair value	0	1
Pension benefits | Free-standing derivatives, assets | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Free-standing derivatives, assets | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	0	1
Pension benefits | Free-standing derivatives, assets | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Free-standing derivatives, liabilities
Components of net periodic cost
Total plan assets at fair value	(9)	(6)
Pension benefits | Free-standing derivatives, liabilities | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	(1)
Pension benefits | Free-standing derivatives, liabilities | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	(8)
Pension benefits | Free-standing derivatives, liabilities | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0
Pension benefits | Free-standing derivatives, other assets
Components of net periodic cost
Total plan assets at fair value	1	1
Pension benefits | Free-standing derivatives, other assets | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	1	1
Pension benefits | Free-standing derivatives, other assets | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	0	0
Pension benefits | Free-standing derivatives, other assets | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	$ 0	$ 0