Benefit Plans - Fair Value of pension plan assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
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		$ 0
Free-standing derivatives liabilities | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value		(3)
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	$ 2,732	$ 2,520
Total plan assets at fair value, allocation (as a percent)	100.00%	100.00%
Investments measured using the net asset value practical expedient	$ 1,975	$ 4,109
Securities lending obligation	(296)	(121)
Derivatives counterparty and cash collateral netting	2	(3)
Other net plan assets	17	20
Total reported plan assets	4,430	6,525	$ 6,987
Pension benefits | Quoted prices in active markets for identical assets (Level 1)
Components of net periodic cost
Total plan assets at fair value	$ 779	$ 506
Total plan assets at fair value, allocation (as a percent)	28.50%	20.10%
Pension benefits | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	$ 1,953	$ 2,012
Total plan assets at fair value, allocation (as a percent)	71.50%	79.80%
Pension benefits | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	$ 0	$ 2
Total plan assets at fair value, allocation (as a percent)	0.00%	0.10%
Total reported plan assets	$ 0	$ 2	2	$ 0
Pension benefits | Equity securities
Components of net periodic cost
Total plan assets at fair value	145	357
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	120	311
Pension benefits | Equity securities | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	25	44
Pension benefits | Equity securities | Significant unobservable inputs (Level 3)
Components of net periodic cost
Total plan assets at fair value	0	2
Total reported plan assets	0	2	0
Pension benefits | Government bonds
Components of net periodic cost
Total plan assets at fair value	1,392	1,264
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	496	58
Pension benefits | Government bonds | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	896	1,206
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	757	696
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	757	696
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	$ 0
Pension benefits | Short-term investments
Components of net periodic cost
Total plan assets at fair value	442	200
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	163	135
Pension benefits | Short-term investments | Significant other observable inputs (Level 2)
Components of net periodic cost
Total plan assets at fair value	279	65
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	1	4
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	1	4
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	(6)	(3)
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	(5)
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	2
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	2
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