Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable	$ 871	$ 649
Accrued Employee Benefits	182	232
Liability for Claims and Claims Adjustment Expense	179	149	$ 164	$ 169
Derivative Liability, Fair Value, Gross Liability	43	95
Deferred Revenue	40	56
Cash collateral received from counterparties	6	10
Other Accrued Liabilities	571	546
Accounts Payable and Accrued Liabilities	$ 1,892	$ 1,737