Retirement-Related Benefits (Narrative) (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Non-U.S. Defined Benefit and Multi-employer Plan
Expected current year contributions to non-U.S. defined benefit plans	$ 600
Year-to-date contributions to non-U.S. defined benefit plans	90
Non-US Defined Benefit Pension Plans
Multi-employer plans/other costs	248	79
Non-US Defined Benefit Pension Plans | SG&A expense | Litigation in Spain regarding defined benefit and defined contribution plans
Multi-employer plans/other costs	$ 230	$ 55	$ 148