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			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	[2]	Jun. 30, 2017	Jun. 30, 2016	[4]
Earnings per share:
Net income (loss) available to common shareholders	$ 344	$ 305	[1]	$ 634	$ 616	[3]
Less: Income allocated to participating securities	4	3		7	6
Earnings per share - basic	340	302		627	610
Earnings per diluted share:
Net income available to common shareholders	344	305	[1]	634	616	[3]
Stock-based awards	0	0		0	0
Net income available to common shareholders plus assumed conversions	344	305		634	616
Less: Income allocated to participating securities	4	3		7	6
Net income allocated to common shareholders	$ 340	$ 302		$ 627	$ 610
Earnings per share:
Net income allocated to common shareholders	741,400,700	759,105,385		744,516,799	766,334,781
Effect of dilutive securities:
Stock-based awards	11,000,000	6,000,000		12,000,000	5,000,000
Net income allocated to common shareholders	752,328,298	764,811,003		756,545,341	771,284,468
Earnings per share:
Earnings per share - basic	$ 0.46	$ 0.4		$ 0.84	$ 0.8
Earnings per diluted share:
Earnings per share - diluted	$ 0.45	$ 0.39		$ 0.83	$ 0.79

[1] A net tax deficiency of $ 5 was reclassified from capital surplus to applicable income tax expense for the three months ended June 30, 2016, related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effe ctive date of January 1, 2016.

[2] A net tax deficiency of $5 was reclassified from capital surplus to applicable income tax expense and average common shares outstanding - diluted were adjusted for the three months ended June 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 for the six months ended June 30, 2016 related to the early adoption of ASU 2016-09 during the fourth quarter of 2016, with an effective d ate of January 1, 2016

[4] Net tax deficiencies of $6 were reclassified from capital surplus to applicable income tax expense and average common shares outstanding - diluted were adjusted for the six months ended June 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 .