Employee Stock-based Incentives - Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Cost of prior grants of restricted stock units (“RSUs”), stock appreciation rights (“SARs”) and performance share units (“PSUs”) that are amortized over their applicable vesting periods	$ 284	$ 292
Accrual of estimated costs of stock-based awards to be granted in future periods including those to full-career eligible employees	235	273
Total noncash compensation expense related to employee stock-based incentive plans	$ 519	$ 565