Derivatives (Details 6) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	$ 56	$ 110
Net Amount of Derivative Liabilities	27	59
Derivatives Subject to Master Netting Agreements
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	55	110
Gross Amount of Eligible Offsetting Recognized Derivative Assets	29	51
Cash Collateral Pledged	0	0
Net Amount of Derivative Liabilities	26	59
Derivatives Not Subject to Master Netting Agreements
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	1	0
Net Amount of Derivative Liabilities	$ 1	$ 0