Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Millions	Jan. 27, 2017	Jan. 11, 2017	Dec. 31, 2016	Oct. 18, 2016	Jul. 18, 2016	Dec. 31, 2015
Subsequent Event [Line Items]
Dividends Payable, Amount Per Share			$ 0.08	$ 0.08	$ 0.08
Short-term Debt			$ 12,673			$ 8,101
Unsecured Debt [Member]
Subsequent Event [Line Items]
Short-term Debt			$ 3,622			$ 3,453
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends Payable, Amount Per Share		$ 0.08
Subsequent Event [Member] | Unsecured Debt [Member] | Committed Funding Facilities Member
Subsequent Event [Line Items]
Short-term Debt	$ 1,300