Employee Benefit Plans Defined Benefit Plan, Change in Obligations and Fair Value (Additional Information) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Other Assets		$ 6,405	$ 5,582
Other Liabilities		$ 2,996	$ 3,198
Pension Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		4.18%	4.44%
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities		$ 80	$ 81
Defined Benefit Plan, Contributions by Employer	[1]	5	5
Common Stock held in Pension Plan		2	1
Other Assets		349	244
Other Liabilities		$ 80	$ 81
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate		3.70%	3.95%
Defined Benefit Plan, Contributions by Employer	[2]	$ 0	$ 0
Other Assets		$ 99	$ 91

[1] Employer contributions represent the benefits that were paid to nonqualified plan participants. Unfunded nonqualified supplemental pension plans are not funded through plan assets.

[2] The Company contributed less than $1 million to the other postretirement benefits plans during both 2016 and 2015.