Employee Benefit Plans (Narrative) (Details) shares in Millions, $ in Millions		12 Months Ended
	Apr. 01, 2021 USD ($) retirees	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement				$ 48
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment				51
Number of retirees | retirees	6,000
Pension settlement		$ (83)	$ 0	0
Percentage of non-matching employer's contribution to eligible participants (as a percent)		1.00%
Employer's Common stock held under 401 (k) plan (in shares) | shares		6.5
Market value of employer's Common stock held under 401 (k) plan		$ 441
Cash dividend received on employer's Common stock held under 401 (k) plan		$ 10
Increase (Decrease) in Obligation, Pension Benefits	$ 700
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocation		100.00%	100.00%
Defined Benefit Plan, Plan Assets, Payment for Settlement		$ 715	$ 18
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement		715	17
Pension settlement		(83)	0	(96)
Accumulated other comprehensive income, unrecognized prior service cost (credit)		(94)
Accumulated other comprehensive income, unrecognized actuarial losses		314
Defined Benefit Plan, Plans with Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit obligation		1,700	2,600
Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation		1,700	2,600
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		1,600	2,500
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets		1,200	1,900
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation		1,600	2,500
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets		1,200	1,900
Accumulated benefit obligation		2,100	2,900
Contributions and expected future benefit payments		$ 28
Pension Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization period of actuarial gains and losses		2 years
Pension Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization period of actuarial gains and losses		28 years
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement		$ 0	0
Pension settlement		0	$ 0	$ (3)
Accumulated other comprehensive income, unrecognized prior service cost (credit)		1
Accumulated other comprehensive income, unrecognized actuarial losses		$ 46
Annual rate of increase in per capita cost of covered health care benefits assumed for transition period (as a percent)		6.10%
Annual rate for per capita cost of covered health care benefits assumed for 2025 and thereafter (as a percent)		4.50%
Year ultimate rate assumed for per capita cost of health care benefits is to be reached		2031
Contributions and expected future benefit payments		$ 15
Other Postretirement Benefits Plan [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization period of actuarial gains and losses		6 years
Other Postretirement Benefits Plan [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization period of actuarial gains and losses		21 years