Employee Benefits (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) employee	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Defined benefit expense	$ 27	$ 25	$ 8
Contributions by employer	$ 171	168	$ 167
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Number of eligible employees for pension plan (in employee) | employee	0
Defined benefit obligation	$ 1,470	1,530
Defined benefit overfunded (underfunded) status	49	(15)
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit obligation	42	4
Defined benefit overfunded (underfunded) status	(42)	(4)
SERP
Defined Benefit Plan Disclosure [Line Items]
Defined benefit obligation	3	69
Defined benefit overfunded (underfunded) status	$ (3)	$ (69)