Derivative Financial Instruments (Hedges) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013 Yr	Dec. 31, 2012 Yr
Cash Flow Hedges [Member]
Unrealized net gains (losses) on cash flow hedges, after tax	$ 2	$ (173)
Estimated amount in AOCI expected to be reclassified within twelve months, after tax	(50)	(37)
Maximum length of time entity has hedged portion of variable cash flows for forecasted transactions	7	0
Pre-tax deferred gain from terminated cash flow hedges recorded in OCI	198	0
Fair Value Hedges [Member]
Pre-tax deferred gain from terminated fair value hedges	0	85
Pre-tax benefits from reductions of interest expense from previous hedge unwinds	$ 89	$ 256