Computation of EPS (Details) (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Computation of EPS
Net income available to common shareholders	$ 425	$ 547	$ 926	$ 757
Weighted average number of common shares	719,080	702,082	715,978	701,245
Effect of dilutive outstanding equity-based awards	9,372	10,779	10,410	10,753
Weighted average number of diluted common shares	728,452	712,861	726,388	711,998
Basic EPS	$ 0.59	$ 0.78	$ 1.29	$ 1.08
Diluted EPS	$ 0.58	$ 0.77	$ 1.27	$ 1.06
Anti-dilutive awards	14,379	30,123	14,815	32,144