Fair Value Significant unobservable inputs (Level 3) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Liability Net, Value	$ (31)	$ 18	$ (31)	$ 18	$ (3)	$ (1)	$ 3	$ 3
Fair Value, Assets Liabilites Net, Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total gains (losses), Included in earnings	(19)	0	(18)	6
Total gains (losses), Included in other comprehensive income	(9)	1	(10)	0
Settlements	0	(4)	(2)	(9)
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss)	$ (14)	$ 1	$ (16)	$ 5