Derivative Financial Instruments (Hedges) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014 Yr	Dec. 31, 2013 Yr
Cash Flow Hedges [Member]
Net unrecognized after tax loss on active hedges recorded in OCI	$ (116)	$ (127)
Net unrecognized after tax gain on terminated hedges recorded in Oci to be recognized primarily 2016 to 2021	127	129
Estimated portion of net after-tax loss on active and terminated hedges to be reclassified from OCI into earnings during the next 12 months	(52)	(50)
Maximum length of time entity has hedged portion of variable cash flows for forecasted transactions	8	7
Fair Value Hedges [Member]
Unrecognized pre-tax gain on terminated hedges to be recognized through 2019	282	326
Portion of pre-tax gain on terminated hedges to be recognized as reduction of interest expense during next 12 months	$ 87	$ 87