Employee Benefit Plans (Pension and Postretirement Plans) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Percentage Of Projected Benefit Obligation Comprised Of Domestic Plan Benefits	86.00%	87.00%
Percentage Of Projected Benefit Obligation Comprised Of Foreign Plan Benefits	11.00%	10.00%
Defined Benefit Plan, Accumulated Benefit Obligation	$ 49,400	$ 48,800
Fair value of plan assets	$ 48,945	$ 47,960
Nonqualified Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage Of Projected Benefit Obligation Comprised Of Domestic Plan Benefits	3.00%	3.00%
Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 1,467	$ 1,650	$ 1,885
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Percent Of Plan Assets Concentrated in Individual Investment	5.00%
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan amendments	$ 0	0
Net settlement and curtailment gain (loss)	$ 2	$ 3	$ 0
Expected return on plan assets, net cost	6.80%	5.70%	5.70%
Fair value of plan assets	$ 316	$ 302	$ 389
Other Postretirement Benefits Plan [Member] | Asset Held in Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	93	105
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan amendments	19	131
Net settlement and curtailment gain (loss)	$ (6)	$ (2)	$ (22)
Expected return on plan assets, net cost	7.10%	6.50%	6.50%
Derivative, Fair Value, Net	$ 345	$ (79)
Fair value of plan assets	$ 48,945	47,960	$ 63,323
Pension Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range Of Growth Seeking Assets In Company's Overall Investment Strategy	46.00%
Range Of Income Generating Assets In Company's Overall Investment Strategy	74.00%
Percentage Of Interest Rate Sensitivity Of Pension Plan Liabilities Fixed Income Portfolio Designed To Hedge	80.00%
Pension Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range Of Growth Seeking Assets In Company's Overall Investment Strategy	26.00%
Range Of Income Generating Assets In Company's Overall Investment Strategy	54.00%
VEBA [Member] | Significant Unobservable Inputs (Level 3) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0