Employee Benefit Plans (Paid Benefit Obligations and Accumulated Benefit Obligations in Excess of Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Accumulated benefit obligation [Abstract]
Projected benefit obligations	$ 1,831	$ 2,441
Accumulated benefit obligations	1,740	2,312
Estimated fair value of plan assets	0	539
Defined Benefit Plan, Plan with Accumulated Postretirement Benefit Obligation in Excess of Plan Assets, Accumulated Postretirement Benefit Obligation	813	868
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligations	1,840	2,469
Accumulated benefit obligations	1,740	2,332
Estimated fair value of plan assets	9	564
Defined Benefit Plan, Plan with Accumulated Postretirement Benefit Obligation in Excess of Plan Assets, Plan Assets	$ 331	$ 355