Accrued Expenses and Other Liabilities (Schedule of Accrued Expenses and Other Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities [Abstract]
Accounts Payable	$ 863	$ 649
Accrued Employee Benefits	227	232
Liability for Claims and Claims Adjustment Expense	173	149	$ 150	$ 169
Deferred Revenue	34	56
Derivative Liability, Fair Value, Gross Liability	30	95
Cash collateral received from counterparties	14	10
Other Accrued Liabilities	551	546
Accounts Payable and Accrued Liabilities	$ 1,892	$ 1,737