Employee Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Target allocation and pension plan asset allocation
Contributions made to defined benefit pension plans	$ 38	$ 9
Estimated fair value of plan assets	206	156	$ 156	$ 206	$ 185	$ 156
Reconciliation of benefit obligation:
Benefit obligation at beginning of year	348	293
Service cost	9	8	10
Interest cost	11	12	11
Actuarial losses	58	50
Plan settlements	(38)	(9)
Benefits paid	(9)	(9)
Other		3
Benefit obligation at end of year	379	348	293
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	185	156
Actual return on plan assets	27	35
Employer contributions	38	9
Plan settlements	(38)	(9)
Benefits paid	(6)	(6)
Fair value of plan assets at end of year	206	185	156
Funded status				(173)	(163)
Expected future benefit payments
2021				10
2022				30
2023				19
2024				22
2025				14
Next five years after year five				77
Components of net periodic benefit cost:
Service cost	9	8	10
Interest cost	11	12	11
Expected return on plan assets	(11)	(10)	(11)
Amortization	7	5	6
Settlement loss recognized	11	2
Net periodic benefit cost	27	17	16
Amounts not reflected in net periodic benefit cost and included in accumulated other comprehensive loss (AOCL) before taxes
Total accumulated other comprehensive loss				112	88
Other disclosures
Pension distribution	32
Deferred compensation paid	32
Contribution expense for multi-employer pension fund, the United Food and Commercial Workers International Union-Industry Pension Fund, which covers certain union employees under a collective bargaining agreement		$ 1	$ 1
Estimated withdrawal liability					14
Time period over which quarterly installment payments will be made		20 years
Defined benefit pension plan
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	$ 185	$ 185		206	185
Weighted-average assumptions
Expected return on plan assets (as a percent)	6.25%	6.25%	6.25%
Long-term rate of increase in compensation levels (as a percent)	4.00%	4.00%	4.00%
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	$ 185
Fair value of plan assets at end of year	206	$ 185
Funded status				(43)	(53)
Expected future benefit payments
Accumulated benefit obligation				157	205
Defined benefit pension plan | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	185	185		206	185
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	185
Fair value of plan assets at end of year	206	185
Defined benefit pension plan | Domestic equity securities
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	84	84		93	84
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	84
Fair value of plan assets at end of year	93	84
Defined benefit pension plan | Domestic equity securities | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	84	84		93	84
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	84
Fair value of plan assets at end of year	93	84
Defined benefit pension plan | Foreign equity securities
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	57	57		64	57
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	57
Fair value of plan assets at end of year	64	57
Defined benefit pension plan | Foreign equity securities | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	57	57		64	57
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	57
Fair value of plan assets at end of year	64	57
Defined benefit pension plan | Fixed income
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	30	30		32	30
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	30
Fair value of plan assets at end of year	32	30
Defined benefit pension plan | Fixed income | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	30	30		32	30
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	30
Fair value of plan assets at end of year	32	30
Defined benefit pension plan | Foreign fixed income mutual funds
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	12	12		15	12
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	12
Fair value of plan assets at end of year	15	12
Defined benefit pension plan | Foreign fixed income mutual funds | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	12	12		15	12
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	12
Fair value of plan assets at end of year	15	12
Defined benefit pension plan | Money market funds
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	2	2		2	2
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	2
Fair value of plan assets at end of year	2	2
Defined benefit pension plan | Money market funds | Level 1
Target allocation and pension plan asset allocation
Estimated fair value of plan assets	2	2		$ 2	$ 2
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	2
Fair value of plan assets at end of year	$ 2	$ 2
Defined benefit pension plan | Minimum
Weighted-average assumptions
Discount rate used to determine obligations (as a percent)				0.70%	2.15%	3.50%
Discount rate used to determine net periodic benefit cost (as a percent)	2.15%	3.50%	2.75%
Defined benefit pension plan | Minimum | Domestic equity securities
Target allocation and pension plan asset allocation
Target Allocations (as a percent)				50.00%
Defined benefit pension plan | Minimum | Foreign equity securities
Target allocation and pension plan asset allocation
Target Allocations (as a percent)				25.00%
Defined benefit pension plan | Minimum | Fixed income
Target allocation and pension plan asset allocation
Target Allocations (as a percent)				20.00%
Defined benefit pension plan | Minimum | Alternative investments
Target allocation and pension plan asset allocation
Target Allocations (as a percent)				5.00%
Defined benefit pension plan | Maximum
Weighted-average assumptions
Discount rate used to determine obligations (as a percent)				2.60%	3.50%	4.50%
Discount rate used to determine net periodic benefit cost (as a percent)	3.50%	4.50%	3.80%
Supplemental executive plans and retirement agreements
Expected future benefit payments
Accumulated benefit obligation				$ 179	$ 104