Income Taxes Items Accounting for Differences between Income Taxes Computed at Federal Statutory Rate and Provision Recorded for Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Income taxes computed at the federal statutory rate																	$ (39)	$ 177	$ 191
Effect of:
Impact of foreign tax differential																	136	(41)	172
State taxes, net of federal benefits																	29	14	1
Tax credits																	(85)	(84)	(24)
Nondeductible compensation																	117	86	72
Domestic production activities deduction																	20	11	0
Other, net																	29	20	16
Provision for income taxes, net	$ (205)	[1]	$ 205	[1]	$ (94)	[1]	$ (73)	[1]	$ (179)	[1]	$ 12	[1]	$ (13)	[1]	$ 18	[1]	$ 167	$ 161	$ 428

[1] The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is due to the effects of rounding and changes in the number of weighted-average shares outstanding for each period.