Employee Benefit Plans Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2018 USD ($)
Pension Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	$ 175	[1]
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	161	[1]
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	161	[1]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	159	[1]
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	159	[1]
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	773	[1]
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months	6	[2]
Defined Benefit Plan, Expected Future Benefit Payment, Year Two	6	[2]
Defined Benefit Plan, Expected Future Benefit Payment, Year Three	6	[2]
Defined Benefit Plan, Expected Future Benefit Payment, Year Four	5	[2]
Defined Benefit Plan, Expected Future Benefit Payment, Year Five	4	[2]
Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter	16	[2]
Plan Trusts [Member] | Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0	[1]
Plan Trusts [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0	[2]
Plan Participants [Member] | Pension Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	7	[1],[3]
Plan Participants [Member] | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 0	[2],[3]

[1] Based on the funding status and ERISA limitations, the Company anticipates contributions to the Retirement Plan will not be required during 2019.

[2] Expected payments under other postretirement benefit plans are shown net of participant contributions.

[3] The expected benefit payments for the SERP will be paid directly from the Company's corporate assets.