EPS (Calculation of Earnings Per Share and the Reconciliation of Earnings Per Share to Earnings Per Diluted Share) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	[1]	Sep. 30, 2017	Sep. 30, 2016	[3]
Earnings per share:
Net income (loss) available to common shareholders	$ 999	$ 501		$ 1,633	$ 1,118	[2]
Less: Income allocated to participating securities	10	5		18	12
Earnings per share - basic	989	496		1,615	1,106
Earnings per diluted share:
Net income available to common shareholders	999	501		1,633	1,118	[2]
Stock-based awards	0	0		0	0
Net income available to common shareholders plus assumed conversions	999	501		1,633	1,118
Less: Income allocated to participating securities	10	5		18	12
Net income allocated to common shareholders	$ 989	$ 496		$ 1,615	$ 1,106
Earnings per share:
Net income allocated to common shareholders	721,280,389	750,885,834		736,686,213	761,147,543
Effect of dilutive securities:
Stock-based awards	12,000,000	7,000,000		12,000,000	6,000,000
Net income allocated to common shareholders	733,284,502	757,855,877		748,706,522	766,775,598
Earnings per share:
Earnings per share - basic	$ 1.37	$ 0.66		$ 2.19	$ 1.45
Earnings per diluted share:
Earnings per share - diluted	$ 1.35	$ 0.65		$ 2.16	$ 1.44

[1] A verage common shares outstanding - diluted were adjuste d for the three months ended September 30, 2016 related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effective date of January 1, 2016

[2] Net tax deficiencies of $ 6 were reclassified from capital surplus to applicable income tax expense for the nine months ended September 30, 2016 , related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effective date of January 1, 2016

[3] Net tax deficiencies of $6 were reclassified from capital surplus to applicable income tax expense and average common shares outstanding - d iluted were adjusted for the nine months ended September 30, 2016 related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effective date of January 1, 2016 .